Japanese Monograph No. 174

OUTLINE OF NAVAL ARMAMENT PREPARATIONS FOR WAR

PART VI

DRAFT

PREPARED BY

MILITARY HISTORY SECTION

HEADQUARTERS, ARMY FORCES FAR EAST

DISTRIBUTED BY

OFFICE OF THE CHIEF OF MILITARY HISTORY

DEPARTMENT OF THE ARMY

HEADQUARTERS

FAR EAST COMMAND

MILITARY HISTORY SECTION, SPECIAL STAFF

JAPANESE RESEARCH DIVISION

Outline of Naval Armament and Preparations for War, Part VI

JAPANESE MONOGRAPH No 174

Through Instructions No. 126 to the Japanese Government, 12 October 1945, subjects Institution for War Records Investigation, steps were initiated to exploit military historical records and official reports of the Japanese War Ministry and Japanese General Staff. Upon dissolution of the War Ministry and the Japanese General Staff, and the transfer of their former functions to the Demobilisation Bureau, research and compilation continued and developed into a series of historical monographs.

The paucity of original orders, plans and unit journals, which are normally essential in the preparation of this type of record, most of which were lost or destroyed during field operations or bombing raids rendered the task of compilation most difficult; particularly distressing has been the complete lack of official strength reports, normal in AG or G3 records. However, while many of the important orders, plans and estimates have been reconstructed from memory and therefore are not textually identical with the originals, they are believed to be generally accurate and reliable.

Under the supervision of the Demobilisation Bureau, the basic material contained in this monograph was compiled and written in Japanese by former officers, on duty in command and staff units within major units during the period of operations. Translation was effected through the facilities of Military Intelligence Service Group, 02, Headquarters, Far East Command.

This Japanese Operational Monograph was rewritten in English by the Japanese Research Division, Military History Section, Headquarters, Army Forces Far East and is based on the translation of the Japanese original Editorial corrections were limited to those necessary for coherence and accuracy.

FOREWORD

This is the last of a series of six monographs in regard to Japan naval armament in preparation for and during the Pacific War.

Additional monographs covering Japan's naval armament plans are.

Mono No

Outline of Naval Armament and Preparations for War, Part I

145

Outline of Naval Armament and Preparations for War, Part II

149

Outline of Naval Armament and Preparations for War, Part III

160

Outline of Naval Armament and Preparations for War, Part IV

169

Outline of Naval Armament and Preparations for War, Part V

172

24 November 1952

TABLE OF CONTENTS

Page

Contraction and Consolidation of Strategic Areas to be Defended at All Costs

1

General Situation

1

Increase in War Production

2

Withdrawals to Shorten the Line of Defense and Concentration of Defensive Power on Inner Lines

7

Preparations Based on Ail-Out Special Attack Tactics

8

Details of Preparations for Special Attack Operations of the Naval Air Forces

12

CHARTS

Chart No 1

Increase and Decrease in Bottoms During the Pacific War

3

Chart No 2

Status of Aircraft for the "Ketsu-Go" Operation

12

Chart No 3

Outline of the Special Attack Production Plan

16

Chart No 4

Construction Schedule of Special Planes, 20 June 1945

16

Chart No 5

Actual Results and Estimate of Production of Special Planes, 15 July 1945

16

Chart No 6

Secret Bases

18

Chart No 7

Status of Bases for Model 43 Oka

18

Chart No 8

Condensed Report of the Results of Tests at Takeyama Base

21

Chart No 9

Results of "Ko-Go" Tests at Kure Navy Yard

21

Chart No 10

Results of Surface and Underwater Special Attack Weapons Preparation

22

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Page

Chart No 11

Table of Organization of Special Attack Squadrons

22

Chart No 12

Location of Special Attack Bases, 15 August 1945

22

APPENDICES

Appendix I

Major Naval Arms and Weapons Produced from January 1944 to Cessation of Hostilities

Appendix II

Agreement between the Army and the Navy Concerning War Preparations for the First Half of Fiscal Year 1945

Appendix III

Naval General Staff Secret Document No 31

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Contraction and Consolidation of Strategic Areas to be Defended at all Costs

General Situation

At the time the War Preparations Plan, Phase Three, was being deliberated, the situation in the Solomons-New Guinea area was rapidly deteriorating. The tremendous amount of equipment able to be produced by the United States as compared with that produced by Japan was having its effect. Taking into consideration her national resources and scientific technical capacity, Japan recognized that it would be impossible to hold her own-on her greatly extended fronts. It was, therefore, decided at a council meeting held in the presence of the Emperor on 30 September 1943, to contract and consolidate the strategic areas at all costs.

The main points decided by the Council, in the presence of the Emperor, were that, by the middle of 1944, strategic preparations would be completed to cope with the Anglo-American offensive; the areas to be held at all costs in the Pacific and Indian Oceans were the Kurile Islands, the Bonin, Mariana and Caroline Islands, western New Guinea, Sunda and Burma, and every effort was to be made to maintain sea communications with these areas.

In accordance with the above, transportation of war supplies to areas outside the areas specified at the conference, which had been conducted up to that time despite heavy losses of warships, transports, aircraft, munitions and men, was to be reduced to a minimum and the main ef-

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fort was to be directed toward the strengthening of defense in the strategic areas to be defended at all costs.

This decision was made too late, however, and even the new line of defense was too extensive for Japan's national resources and military capabilities. The burden of immediate war preparations, therefore, was not eased, and, at the same time, the difficulties in transportation of war supplies mounted daily, caused by the increasing activities of enemy submarines and aircraft. This greatly delayed the bolstering of defenses in the various areas.

Increase in War Production

As stated in Monograph 172, the Navy had embarked upon the Revised Fifth Naval Armament Expansion Program. This called for the nation, as a whole, to muster its entire power in order to attain the production goal set forth by the "Joint Army-Navy Study in regard to the Material Mobilisation Plan for 1943." During the second half of 1943 and the first half of 1944, although production failed to reach the goal set forth in the Revised Fifth Plan, great advances were made, and production reached a peak unprecedented in Japan's history. Had the American invasion of the Marianas, Carolines and Philippines been delayed approximately six months, the implements of war produced by this greatly stepped-up productive effort would have had a marked effect on the war effort.

It is interesting to note that the upward trend in production, which was not affected by the loss of Saipan or Palau, took a sharp downward

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plunge after the line of communications to the Southern Areas was severed following the Battle of Leyte and also after Japan proper was exposed to air raids.

The major arms and weapons required for naval operations which were produced from January 1944 to the end of the war are shown in Appendix I.

Although construction of merchant ships was also greatly accelerated by the drastic measures adopted by the Japanese Navy, ship losses, as a result of enemy action, greatly exceeded the construction tonnage, sharply reducing available merchant ships. This was felt to be one of the main reasons for Japan's defeat in the Pacific War.

Chart 1 shows the increase and decrease in bottoms during the Pacific War.

The intensification of war preparations at the front, which was conducted on the basis of the conference in the Imperial Presence on 30 September, was primarily aimed at training and replenishing the fleet and strengthening defensive power in key areas. However, the fleet training did not progress satisfactorily because the greater part of our air strength had to be diverted to the Solomons and New Guinea areas to fight battles of attrition aimed at slowing the enemy's advance. In early February 1944, the Marshall Islands were occupied by the enemy. This meant that our key areas were directly threatened by the enemy. On 17 February, Truk Island, the anchorage of the main force of our fleet, was subjected to a formidable air raid by an enemy task force. This forced the greater part of our surface units to retreat toward Palau,

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Chart No 1

Increase and Decrease in Bottoms During the Pacific War (Quantities in thousands of gross tons)

Period

Increase

by

Construction

Decrease

by Losses

Decrease

Total

Percentage Available

it the outbreak of the war

6,384.0

100

December 1941

44.2

51.6

7.4

6,376,6

99

December 1942

661.8

1,095.8

434.0

5,942.6

93

December 1943

1,067.1

2,065.7

998.6

4,944.0

77

December 1944

1,735.1

4,115.1

2,380.0

2,564.0

40

1945 (up to august)

465.0

1,562.1

1,097.1

1,466.9

23

At the end of the war

1,466.9

23

Remarks: The above table shows statistics on steel ships of over 100 tons.

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Davao and Lingga areas. Under these circumstances, it was practically impossible to continue fleet training. Moreover, the activities of enemy aircraft and submarines made our sea communications more and more difficult and transportation of personnel, weapons and other supplies to the Fleet were seriously hampered.

The following is an outline of the measures taken for strengthening defenses in the key areas up to the time of the Leyte Operation, including the Battle of Saipan. This covers approximately one year, to the latter part of October 1944.

Air Defense Units: It was decided to activate 103 air defense units and to dispose them at strategic points on the periphery of the key area, and also at such locations inside the area as Formosa, Ryukyu and Bonin Islands. Upon arrival at their destination, such units were to become an organic part of local base forces or guard units.

The original plan called for Type A air defense units, to be equipped with six antiaircraft guns (12.7cm) and two searchlights, and Type B units, to be equipped with 24 25mm machine guns as their basic equipment. The shortage of antiaircraft guns, however, mads activation of Type A units practically impossible. Hence, most of the units that ware sent to the front were Type B and naturally their defensive power was not great. However, losses at sea were only three of the 103 units. Insofar as the number of units was concerned, the scheduled disposition was generally successful. It was also planned to reinforce the front with more antiaircraft guns and mounts as soon as such equipment became avail-

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able. This plan, however, never materialized because of the drastic changes in the war situation.

Construction Units: Arrangements were made to activate 25 construction units and to dispatch them, according to the following schedule, to expedite completion of airfields and the strengthening of the defense setup in the areas concerned:

South Seas Area (Truk, Saipan, Guam and Palau):

10 construction units

(Two of these units were later reorganized and diverted to other areas following the sinking of their transports)

Western New Guinea Area:

4 units

Ambon, Kai and Aroe Islands:

5 units

Philippines:

3 units

Andaman Islands:

3 units

Each unit was composed of from 700 to 1,000 personnel and was equipped with the necessary construction material, transportation equipment and light weapons. It was no easy matter to send these units forward, not only because of the large amount of transportation required but also because of the debarkation facilities necessary when they arrived at their destination.

As only very few special land combat units (guard units) were activated during this period, it was necessary to station Army troops on even small isolated islands, in accordance with the fundamental concept that the Army would constitute the main force in land combat. At the same time, steps were taken to coordinate the command system of the Army

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and the Navy. Naval units were provided with as many land combat weapons as possible regardless of their assigned areas in order to strengthen the over-all defensive power.

Other major steps taken at this time were: activation and disposition of transport units to increase local transport capacities; strengthening of such organs as the construction and repair departments and air depots to raise construction and repair efficiency in each sector; dispatching of torpedo-adjustment squads as part of the measure to increase the efficiency of supply and maintenance; assignment of tactical guidance squads and technical guidance squads for the improvement of fighting power and techniques; installation of radar equipment at the front, and establishment of personnel recruitment sections in all area fleet headquarters, to which several hundred reserves were assigned.

Despite these efforts, the rapid decline of Japan's national power and industrial potential could not be halted. The main reasons for this were that the implementation of the decisions cams too late; the else of the defensive sphere was too great for Japan's national and war potential; United States forces were driving westward with overwhelming strength through the Mariana and New Guinea areas, making lightening advances, and Japan's surface supply lines were under increasing pressure. This was especially true after the middle of 1943, when communications between the Southern Region and Japan proper were seriously menaced through lack of air supremacy in the Mariana, Caroline and Philippine areas.

--6--

Efforts to strengthen Japan's defensive power merely resulted in a situation where in an effort to defend all points, none were strong. This was attributed to failure to appraise the situation correctly and to adopt a thorough priority system for the areas to be defended.

Withdrawals to Shorten the Line of Defense and Concentration of Defensive Power on Inner Lines

In February 1944, just as several defensive projects, based on the national policy as agreed at the Conference in September 1943, were being put into effect, United States forces, which had already occupied the Marshalls area, launched an all-out air attack against Truk. Next, during the latter part of March and early April, they launched large scale air attacks against the Palau area. Simultaneously, they occupied the northern coast of New Guinea and continued their advance. In the latter part of May they succeeded in seizing Biak Island. Subsequently, on 9 June, they launched operations to occupy Saipan.

The Navy, based on its estimate that the battle for the Marianas would constitute the decisive battle of the war between Japan and the Allies, carried out "A-GO" Operations, throwing almost the entire fleet into the fray. Despite desperate fighting, the battle situation became worse and the Japanese forces retreated after their air and surface forces had sustained critical losses. It was felt that prospects of victory were fast fading with the defeat of the forces in the Marianas area.

The tempo of advance of the United States forces increased steadily. They occupied Tinian Island in July and Peleliu and Morotai Islands by

the middle of September. In October, enemy task forces conducted air

7

raids on Formosa and the Ryukyus. On 20 October, the enemy launched a campaign to occupy the Leyte Gulf area. At this juncture, our fleet, although not fully recovered from the damage sustained in the "A-GO" Operations, and consequently unprepared for a decisive battle, launched a desperate assault upon the enemy with its entire forces. Because of the enemy's air supremacy, however, our fleet was dealt a near fatal blow in this engagement. This resulted in air and sea supremacy, which the Japanese forces had maintained for years in the Far East, being completely yielded to the enemy.

The Japanese Navy, under the circumstances, was confronted with the necessity of drastically shortening its defense lines. It was decided to limit the key area to the area extending from the Kuriles to Formosa, and, at the same time, to establish impregnable defenses on Japanese islands south of the Homeland as well as on Iwo Jima and the Ryukyus. The greatest defensive strength was to be concentrated on Iwo Jima and Okinawa. These emergency changes in policy were carried out within the required time limit because of the proximity of the involved areas to the Homeland, and, at the same time, steady progress was made in the fortification of the inner sectors.

Preparations Based on All-Out Special Attack Tactics The concept of special attack tactics (the tactic of resorting to one-way or suicidal missions for certain destruction of the target) was not entirely new in the history of the Japanese Army and Navy. The Port Arthur blockade in the Russo-Japanese War, the demolition mission of the

--8--

three demolition tube heroes (Nikudan-Sanyushi) in the Chine Incident and the midget submarines employed at Pearl Harbor, all possessed some features of special attack tactics. There are also many instances in the history of Japan in which men voluntarily acted in a manner similar to a special attack mission, but these acts were not specifically ordered by their superiors. The attacks carried out by the Kamikaze Special Attack Unit and the Type A Midget Submarine Unit (Cebu) during the operations in the Philippines area, during and after October 19143, were probably the first attack missions that were planned and ordered by competent commanders. The results achieved by these special attack units were unexpectedly good in comparison to the small force committed. However, it was felt that it was a great tragedy that Japanese field commanders were forced to resort to such tactics because of the rapidly deteriorating situation resulting from the enormous difference in fighting power between the Japanese and Allied forces.

These desperate attack tactics employed by field forces were inevitably reflected in the policies adopted by those concerned with war preparations. Urgent demands for the production of weapons suitable for these special attack tactics originated in the Naval General Staff and immediate response was given to the commands by the Navy Ministry. Inasmuch as the Japanese Navy had been studying weapons for this type of warfare for some time, naval authorities were fairly optimistic regarding the realisation of the project. The greatest difficulty was that the immediate need for such weapons allowed little time for trial manu-

--9--

facture, tests and research.

In October 1943, as a result of negotiations between the Navy Ministry and the Naval General Staff, the following agreement was reached:

The Oka type aircraft (Maru Dai), which had already been tested and approved for special attack purposes, would be used. The Kaiten (commonly known as human torpedoes) and the Shinyo (commonly known as crash boats), in addition to the Type A midget submarine which had already been produced, would be used for surface attacks. Trial manufacture and test runs were made where necessary, and activation of training units was begun.

By adopting latent plans, a variety of new weapons for special attack tactics was produced by the and of 1944. Mass production of such weapons as aircraft known as the "Shusui" and "Kikka", and surface and underwater weapons known as the "Koryu" and "Kairyu" were planned and initiated. In addition, numerous other latent designs were adopted and produced.

In February 1945, the outcome of the Philippines campaign had been decided and, by the end of the same month, the supposedly impregnable fortress of Iwo Jima had been lost after furious fighting. It became increasingly clear that the enemy was about to launch large scale air raids against the Japanese Homeland. Under the circumstances, as were forced to concentrate our war preparations on the production of aircraft and special attack weapons and the completion of defenses for the decisive battle for the Homeland. In view of this situation, the Japanese

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Navy dispersed its production facilities while maintaining a maximum output, strengthened air defenses and, at the same time, initiated all-out war preparations based on special attack tactics.

All war preparations were executed in close cooperation with the Army and each service augmented the deficiencies of the other. This was clearly indicated in the agreement reached between the Army and Navy High Commands on 1 April 1945 (Appendix II).

In accordance with this agreement, on 6 April 1945, the Naval General Staff held a conference with the Navy Ministry in order to decide on the war preparations to be made during the first half of the fiscal year 1945. Details of this conference are given in Naval General Staff Secret Document No 31, 6 April 1945 (Appendix III).

The Navy Ministry completed all research work and reached full agreement with the War Ministry. Although some slight differences in estimates had to be adjusted, the Navy Ministry mapped out a plan of execution which was generally in line with the Naval General Staff's demand and devoted itself to its enforcement.

In the meantime not only did Iwo Jima fall in late February and the Okinawa Invasion Operation begin in early April, but the Homeland was also subjected to large scale day and night air attacks, which occurred almost continuously after the beginning of March. This resulted in heavy damage to personnel and equipment and gravely threatened communications with China and Korea. As a result, the nation's resources, war potential and productivity began to show a rapid decline.

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Detailed plans were made to ready a total of 5,000 standard aircraft, including those newly built or repaired, to equip most of them with special attack equipment and, at the same time, to accelerate as much as possible mass production of special attack aircraft. As far as standard aircraft was concerned, we fell only slightly short of our goal. However, production of special type aircraft lagged considerably, especially the "Shusui", "Ki 115" and "Kikka" types. Although these latter were begun, they were not completed in time to contribute to the war effort.

The status of aircraft for the "Ketsu-Go" Operation, (Homeland Decisive Battle) as of 15 July 1945, was as shown on Chart 2.

Details of Preparations for Special Attack Operations of the Naval Air Forces

First Phase: Since operations on the Japanese mainland itself were considered inevitable as the next phase of operations at the time of the commencement of the Iwo Jima Operation in February 1945, a plan was formulated on 1 March to reorganize the entire naval air forces, primarily for the purpose of launching special attacks. On the same day, the Naval Combined Air Training Command was reorganized into the Tenth Air Fleet and incorporated into the Combined Fleet. Because of the acute shortage of aircraft, as well as fuel, at that time, priority was given to the training of special attack units and training of flight personnel, in general, had to be temporarily suspended. With preliminary training and preparations for converting training aircraft into special attack planes gener-

--12--

Chart 2

Status of aircraft for the "Ketsu-Go" Operation

No. of Aircraft

3d Air Fleet

5th air Fleet

10th air Fleet

Total

Type of Aircraft

Allot

Opnl

Allot

Opnl

Allot

Opnl

Allot

Opnl

"Ko"-type Fighters

312

200

242

141

119

75

673

416

"Otsu"-type Fighters (Interceptor)

137

50

136

55

3

2

276

107

"Hei"-type Fighters (Night fighter)

133

91

28

16

161

107

Bombers

88

60

166

111

254

171

Carrier-bombers

157

113

119

99

99

65

375

277

Carrier-based Attack Planes

90

80

52

44

65

24

207

148

Land-based Bombers

40

32

49

40

89

72

Land-based Attack Planes

25

12

60

48

112

63

197

123

Land-based Recon Planes

49

31

55

16

104

47

Seaplanes

152

120

71

69

223

189

Intermediate Trainer

478

275

1,106

978

659

445

2,243

1,698

"Shiragiku" Utility Trainer

167

131

238

174

19

15

424

320

Total

1,740

1,135

2,244

1,740

1,242

800

5,226

3,675

Abbreviations: Allot Allotment Opnl Operational

ally reaching completion in the middle of May, the 11th Air Flotilla, whose strength was approximately half that of the Tenth Air Fleet, and one-half of the 13th Air Flotilla resumed training.

The bombs to be loaded on the training aircraft which had been converted into special attack planes were as follows:

Type of Aircraft

Bombs (kg)

Number

Type-93 Intermediate Trainer

250

1

Type 2 Intermediate Trainer

250

1

SHIRAGIKU Utility Trainer

250

2

Type-94 Reconnaissance Seaplanes

250

2

Type-95 Reconnaissance Seaplane

250

1

Type Zero Reconnaissance Seaplane

250

2

Type Zero Observation Plane

250

1

Type Zero Training Fighter

250

1

Type Zero Carrier Fighter

250 or 500

1

1

Second Phase: The enemy landed on Okinawa in late March 1945 and as hostile attacks against the Japanese mainland became imminent with the unfavorable conclusion of operations in this area in late June, a speedy completion of preparations for the decisive battle on the mainland became imperative. It was estimated at that time that the enemy invasion of the mainland, anticipated about September at the earliest, would be directed against the southwestern part of Japan proper and that the first wave of the enemy invasion forces would comprise approximately 10 divisions carried by 1,000 transports. It was also estimated that if army and naval

--13--

air forces could succeed in sinking half of the transports within the first ten days of the landing, the enemy's attempt could be smashed. On the basis of the above estimate, the Navy undertook to construct approximately 5,000 standard aircraft by the middle of August.

Furthermore, with a view to compensating for losses and preparing for the second and succeeding assaults of the enemy, the need for special aircraft, taking into consideration such factors as aircraft, fuel and flight personnel, became absolutely imperative. The number of standard aircraft to be built was estimated at 5,000 on the basis of the following figures.

Number of enemy vessels to be sunk:

500

Estimated ratio of hits by suicide planes (based on battle experience gained at Okinawa)

Against the carrier striking forces

1/9

Against troops transports:

1/6

Number of aircraft required against troop transports:

3,000

In addition to the above, taking into consideration the condition of our aircraft at that time, approximately 350 planes were to be assigned to attacks against the carrier striking force and, taking their actual operating capacity and losses prior to the operation into consideration, the number of aircraft required was estimated at 5,000.

In carrying out the decisive battle on the mainland, the naval air forces planned to thwart the maneuverings of the enemy's carrier striking force with one element and attack the troop transport with their main

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Matters to which special attention was given for the maximum utilization of the entire naval air strength, as mentioned above, were as follows: speedy preparation of standard aircraft; speedy preparation of special aircraft; construction and strengthening of air bases, and measures for increasing the efficiency of the special attack planes.

a. Speedy preparation of standard aircraft:

(1) Measures taken to secure aircraft productions The growing intensity of enemy air attacks, as well as the confused state of production and transportation, seriously hampered production of new aircraft. Especially, because of heavy damage to engine plants, production of engines did not keep pace with production of fuselages. Therefore, every effort was made to secure the production of new aircraft by equipping newly-built fuselages with repaired engines.

(2) Acceleration of aircraft repairs: Among the aircraft requiring repairs at that time, the work on approximately 700 planes was expected to be completed by the middle of August. To facilitate maintenance of these aircraft, repair teams, organized by mobilising all technicians of the Air Technician Depot, the Yokosuka Naval Air Group and the research organs of each construction and repair unit, were dispatched to the bases.

(3) Equipping standard aircraft with special attack weapons: All aircraft, except training seaplanes, were equipped with special attack weapons.

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b. Speedy preparations of special aircraft: To supplement the shortage of standard aircraft, construction of special aircraft was required. From the viewpoint of battle preparations, these special attack aircraft, which had originally been designed for special attack purposes, had many advantages compared with the standard aircraft.

Because of the decrease in production and repair capacities due to enemy sir raids and the lack of training for flight personnel, and because of the shortage of aviation fuel, standard aircraft could not meet even half the operations requirements either in quality or quantity. Therefore, special aircraft were required to satisfy the following general conditions: A high ratio of hits (by the adoption of special attack methods): maximum effectiveness: economy of materials; simplicity of operation; simplified training (so that the planes could be operated by young flight personnel); economy of fuel, and high performance.

The plans for the production of special planes and the actual results achieved are shown on Charts 3, 4 and 5.

c. Maintenance and strengthening of air bases: Since the interceptor fighters and the antiaircraft defense capabilities on the ground were inadequate and as aviation fuel was running low, also there was a great strength disparity between friendly and hostile air forces, restrictions on the aggressive use of interceptor fighters were inevitable. Therefore, the adoption of an effective plan for ground defense against heavy air attacks and for the preservation of the necessary air strength until the decisive battle on the Homeland was imperative.

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Chart 3-a

Outline of the Special Attack Production Plan

Kikka

Objective

1

Acquisition of land attack planes suitable for attacks on enemy ships approaching within a short distance. To be mass production.

Type

2

Turbine-rocket twin-engined monoplane

Principal Measurement (Meters)

3

Smallest possible type. Measurement when wings are folded:

Full width: 5.3

Full length: 9.5

Full height: 3.1

Engines to be Installed

4

Two TR-12 Engines

Crew

5

One

Capacity and Armament

Maximum

Speed

(Knots)

6

335 Close to sea level.

365 At an altitude of 6,000 meters

Range

7

200 miles close to sea level

300 miles at an altitude of 6,000 meters

Climbing Power

8

Landing

Speed

(Knots)

9

80

Bomb Load (kg)

10

500

Radio Equipment

11

Model 3, Type-1 Radio-telephone set

Receiver only

Air Groups in Charge (Date of Activation)

12

724th Air Group (1 July 1945)

Remarks

13

Undergoing experimental production and tests. About six months behind the scheduled date of completion and still incomplete.

Chart 3-b

Outline of the Special Attack Production Plan

Oka

Type 11

Type 22

1

Acquisition of special attack gliders that may be released from the Type-1 land attack plane

Acquisition of special attack planes which may be released from "Ginga" and which are capable of .flying by their own power

2

Powder-rocket midwing monoplane

Rocket-engined midwing monoplane

3

Pull width: 5.6

Pull length: 6.06

Full height: 1.16

Full width: 4.12

Full length: 6.88

Full height: 1.15

4

Three powder rockets

One Tsu-11 Engine

5

One

6

7

20,000 meters when released at a speed of 250 knots at an altitude of 3,500 meters

50 miles when released at sea level.

70 miles when released at a speed of 240 knots at an altitude of 4,000 meters

8

9

10

1,200

600

11

12

721st Air Group (1 Oct 1944)

722d Air Group (15 Feb 1945)

13

Used in the Okinawa operation and proved to have excellent performance

Experimental production was completed. Although good results were obtained there was no opportunity to use the plane in battle

Chart 3-c

Outline of the Special Attack Production Plan

Oka

Shusui

Type 43

1

Acquisition of special attack planes which may be released from the "Renzan" or catapulted from the ground

Acquisition of rocket-engined interceptor fighters with a great capacity

2

Turbine-rocket midwing monoplane

Rocket-engined tailless monoplane

3

Full width: 9.0

Full length: 8.16

Full height: 1.15

Full width: 9.5

Full length: 5.85

Full height: 2.7

4

One NE-20 Engine

One KR-10 Engine

5

One

6

10,000 meters

7

5.5 minutes after climbing to an altitude of 10,000 m at a maximum speed of 432 knots

8

Takes 3.5 minutes to climb to an altitude of 10,000 meters

9

10

800

11 30mm machine guns

11

Receiver only

Receiver only

12

725th Air Group (1 Jul 1945)

312th Air Group (5 Feb 1945)

13

Now undergoing experimental production and tests. For coastal defense purposes, this type of plane which may be catapulted from the ground, is under production in great numbers.

Test flights were undertaken twice, but failed owing to defective engines, and the crew perished. Experimental production carried out jointly by the Army and Navy.

Chart 3-d

Outline of the Special Attack Production Plan

Toka

KI-115

Baika

1

"KI-115" plane with "HA-33" engine

Acquisition of special attack planes in which various types of engines such as the "Kotobuki", "Sakae", "Kinsei" and "Zuisei" nay be installed

Acquisition of special attack gliders designed to attack small landing craft approaching within a short distance

2

Single-engined low-wing monoplane

Single-engined low-wing monoplane

Rocket-engined low-wing monoplane

3

Full width: 6.72

Full length: 8.50

Full height: 3.10

4

One HA-33 Engine

Rocket engine built fa experimental purposes

5

One

One

One

6

280 . . . At an altitude of 4,200 m

250

7

Approximately 600 miles

150 miles

8

9

10

500

500

250

11

Receiver only

Receiver only

12

13

Row undergoing experimental production and tests. Converted Army planes

Now undergoing experimental production and tests. Same type as the Army plane built for experimental purposes.

War ended while the demand for experimental production was under discussion

Chart 4

Construction Schedule of Special Planes

(20 June 1945, First Section, General affairs Bureau, Aeronautical Department)

May

Jun

Jul

Aug

Sept

Oct

Nov

Dec

Oka (Model 22)

6

49

30

50

60

60

60

Oka (Model 43)

2

10

22

38

65

80

Kikka (By Aeronautical Department)

Experimental

12

Manufacture

13

125

Final

11

Kikka

(By Naval Technical Department)

10

40

Shusui

35

90

145

225

Ki 115

10

150

320

400

Chart 5

Actual Results and Estimate of Production of Special Planes

(15 July 1945, Second Section, General Affairs Bureau, Aeronautical Department)

Type

Name of Manufacturer

Apr

May

Jun

Jul

Aug

Sept

Shusui

Mitsubishi Co

4

5

14

35

Japan Aircraft Co

1

7

22

50

Fuji Co

1

3

Kikka

First Depot

1

10

30

45

First Air Depot

(2 Tng)

5 - (3 Tng)

Kyushu Aircraft Co

5

15

Naval Technical Depot

Oka

(Model 22)

First Technical Depot

Aichi Co

5

20

40

Oka

(Model A3)

First Technical Depot

8

12

12th Air Depot

Aichi Co

Ki 115

Naval Technical Dept

40

Showa Co

10

Abbreviation: Tng Training Plane

On the other hand, in order to effect maximum utilization of the counterattacking capabilities of our aircraft within the shortest possible time (in approximately 10 days) against an enemy invasion of the Homeland, training planes of poor maneuverability and special planes had to be assigned in advance to areas near the anticipated invasion point. Since special installations were necessary for these special planes, because of their characteristics, the bases then in use were inadequate. Accordingly, maintenance of the bases was carried out in the following phases.

Strengthening of established bases: To strengthen the 70 established land plane bases and the 24, seaplane bases in the Homeland, construction and maintenance of taxi strips, plane dispersal shelters, covered revetments and tunnels and the speedy establishment of underground as well as dispersed installations for quarters, communications and construction apparatus were undertaken with the time of completion set for the middle of August. The location of the established bases at that time was as follows:

Location

Land-plane Bases

Seaplane Bases

Total

Hokkaido

6

1

7

Ou District

6

2

8

Kanto District

11

4

15

Chubu District

9

2

11

Kinki District

4

3

7

Chugoku District

3

2

5

--17--

Shikoku District

2

7

Kyushu District

19

7

26

Korea

7

1

8

Total

70

24

94

Maintenance of secret basest Construction of secret bases (called pasture ground) throughout the country for dispersal and readiness, or for attack bases, of the special attack units, which consisted primarily of training land planes, and maintenance of the western and eastern parts of the mainland by the target dates of 15 August and the end of September respectively, were planned and carried out. In view of the nature of the above bases, attention was paid to camouflage from the time of construction. They were maintained by taking special precautionary measures, such as leaving houses and trees in the secret bases intact until the air units advanced to the bases. The location of the secret bases known as pasture ground was as shown on Chart 6. Chart 7 gives the location of bases prepared for Model 43 Oka special planes in accordance with Yokosuka Naval District Top Secret Order No 496, in May 1945.

In addition, the Osaka Guard District planned to establish six catapults and prepare 25 sheds of Oka bombs in the vicinity of Tanabe.

d. Measures to increase the effectiveness of the special attack planes: Special attack planes were used for the first time in the Philippines in 25 October 1944. They produced not only psychological effects, but also actually inflicted heavy damage on the enemy. This

method of attack was made possible by the imbued patriotism of all com-

--18--

Chart 6-a

Chart Showing Secret Bases (Called Pasture-Ground)

District

Name

Runway

Prefecture, County, Village

Remarks

Yokosuka

Yodanhara

50 x 1,200; extension made to the east & west

Miyagi Ken, Kurihara Gun, Fujisato Mura

Generally completed at the end of August

Babadaira

60 x 800; SN

Fukushima Ken, Adachi Gun, Oyama Mura

Generally completed

Miyota

60 x 800

Fukushima Ken, Tamura Gun, Moriyama Machi

Generally completed at the end of July

Asakawa

70 x 500; EW 30 x 600; SN

The Suigun Line (Iwagi Asakawa)

Generally completed

Ebigashima

60 x 800

Ibaragi Ken, Makabe Gun, Omura

Generally completed at the end of July

Ohatake (Fujisawa)

60 x 800

Ibaragi Ken, Niihari Gun, Fujisawa Mura

Generally completed

Katsuragi

60 x 800

Ibaragi Ken, Tsukuba Gun, Katsuragi Mura

Generally completed

Okabe

60 x 800

Ibaragi Ken, Inashiki Gun, Okada Mura

Generally completed at the end of August

Negata

(2d Kisarazu)

50 x 600

Chiba Ken, Kimitsu Gun, Negata Mura

Generally completed at the end of August. (Hitachi Aircraft Co (Hitachi Sha))

Oyana

(2d Atsugi)

100 x 1,800 NNW

Kanagawa Ken, Koza Gun, Ayase

Same as above

Iwamurada

50 x 600; NNW

Nagano Ken, Minami-saku Gun, Iwamurata Machi

Generally completed at the end of August

Chart 6-b

Chart Showing Secret Bases (Called Pasture-Ground)

(Cont'd)

District

Name

Runway

Prefecture, County, Village

Remarks

Yokosuka

Yoshioka

(2d Oi)

60 x 900; NNW

Shizuoka Ken, Oi, Wadaoka Machi

Generally completed

Bazu

50 x 600;

extension made

Aichi Ken, Nukada Gun, Miai Mura (TN Presumably Kawai Mura)

Generally completed

Iwatsu

Aichi Ken, Nukada Gun, Iwatsu Mura

Generally completed at the end of July. (Nakajima Aircraft Co (Nakajima Sha))

Takanoo (3d Susuka)

60 x 1,200; NW

Mie Ken, Kawage Gun, Takano Mura (TN Presumably Takanoo Mura)

Same as above

Meizuru

Takegata (TN

Presumably

Masugata)

60 x 800

Yamagata Ken, Mogami Gun, Yamuki Mura

Generally completed at the end of July

Tamanohara (TN Presumably Tamano)

60 x 800

Yamagata Ken, Kita-murayama Gun, Tamanohara Mura (TN Presumably Tamano Mura)

Same as above

Yonasawa

60 x 800

Yamagata Ken, Nishi-Murayama Gun, Shigematsu Mura (TN Presumably Takamatsu Mura)

Same as above

Urushiyama

300 x 1,000; SN

Yamagata Ken, Higashi-Murayama

Already established (Hitachi Aircraft Co (Hitachi Sha))

Chart 6-c

Chart Showing Secret Bases (Called Pasture-Ground)

(Cont'd)

District

Hans

Runway

Prefecture, County, Village

Remarks

Maizuru

Tazu

50 x 700; extended to 1,200

Ishikawa Ken, Kashima Gun, Soma Mura

Generally completed at the end of July. (Nakajima Aircraft Co (Nakajima Sha))

Atago (Fukui)

50 x 700; extended to 1,200

Fukui Ken, Nibu Gun, Takano Mura (TN Presumably Yoshino Mura)

Generally completed at the end of July (Aichi Aircraft Co (Aichi Sha))

Shiga

60 x 1,000; NNE

Shiga Ken, Shiga Gun, Shimo-sakamoto Mura

Same as above

Hikone

30 x 600 (60 x 1,200)

Shiga Ken, Inuyama Gun

30 x 600 . . . completed at the end of July.

60 x 1,200 . . . completed at the end of August.

(Mitsubishi Aircraft Co (Mitsubishi Sha))

Ayabe

30 x 600; EW

Kyoto Fu, Ikaruka Gun, Ikuda Mura

Generally completed

Oshinotsu

30 x 600

Tottori Ken, Seihaku Gun, Oshinotsu Mura

Same as above

Naoe

30 x 600; SW

Shinano Ken, Hinokawa Gun, Naoe Mura

Same as above

Osaka

Ichiba (2d Tokushima)

100 x 1,200; EW

Tokushima Ken, Awa Gun, Ichiba, Mura

Generally completed (Kawanishi Aircraft Co (Kawanishi Sha))

(2d Yamato)

Chart 6-d

Chart Showing Secret Bases (Called Pasture-Ground)

(Cont'd)

District

Name

Runway

Prefecture, County, Village

Remarks

Kure

Kuniyasu (Kabe)

60 x 1,200; KE

Hiroshima Ken, Takata Gun, Neno Mura

Generally completed at the end of August

Shimokawara

30 x 600; NNE

Hiroshima Ken, Saeki Gun, Sakagami Mura

Same as above

Shiroyama (Iwakuni)

30 x 600; 2 runways, NE

Yamaguchi Ken, Kuga Gun, Fujisawa Mura (TN Presumably Fujikawa Mura)

Same as above

Osaba

30 x 600; NNW

Yamaguchi Ken, Yoshiki Gun, Osaba Mura

Same as above

Akago

30 x 600; NW

Yamaguchi Ken, Mine Gun, Akago Mura

Same as above

Tano

30 x 600; NW

Shima Ken, Shuso Gun, Tano Mura

Same as above

Takenoshita

30 x 600; EW

Ehime Ken, Onsen Gun, Haishi Mura

Same as above

Kamimurashima

30 x 600; EW

Shima Ken, Kita Gun, Sugeta Mura

Same as above

Niida

(2d Kochi)

100 x 1,800; EW

Kochi Ken, Kami Gun, (TN Presumably Takaoka Gun), Niida Mura

Generally completed at the end of August

Kubokawa

(3d Kochi)

60 x 1,200; SN

Kochi Ken, Takaoka Gun, Kubokawa Machi

Same as above

Saikawa

30 x 600; NE

Fukuoka Ken, Miyako Gun, Saikawa Mura

Same as above

Chart 6-a

Chart Showing Secret Bases (Called Pasture-Ground)

(Cont'd)

District

Name

Runway

Prefecture, County, Village

Remarks

Kure

Nakatsu

30 x 600; HW

Oita Ken, Shimoge Gun, Tsurui Mura

Same as above

Kusaji

30 x 600; EW

Oita Ken, Nishi-Kunisaki Gun, Kusaji Mura

Same as above

Usuki

30 x 600; NS

Oita Ken, Kita-amabe Gun, Usuki Machi

Same as above

Totsugi

80 x 1,500; NE

Oita Ken, Oita Gun, Totsugi Mura

Same as above

2d Iwakuni

50 x 520; NS

Yamaguchi Ken, Kuga Gun, (TN Presumably Kumage Gun), Marifu Mure

The northern part adjoins the airfield

Sasebo

Naokata

30 x 600; NNW

Fukuoka Kan, Onga Gun, Tonno Mura

Emergency runway: generally completed on 15 July

Tatara

28 x 1,000; NS

Fukuoka Ken, Chikushi Gun, Kasuga Mura

Generally completed

Ogi

30 x 600; ENE

Saga Ken, Ogi Gun, Ogi Mura

Same as above

Ainoura

30 x 600; ESS

Nagasaki Ken, Kita-matsuura Gun, Ainoura

(Drill ground of marine corps)

Kawatana

30 x 600; EW

Nagasaki Ken, (Higashi)-Sonoki Gun, Kawatana Cho

Generally completed (Factory site)

Chart 6-f

Chart Showing Secret Bases (Called Pasture-Ground)

(Cont'd)

District

Name

Runway

Prefecture, Country, Village

Remarks

Sasebo

Shimabara

30 x 600; NNW

Nagasaki Ken, (Shimabara Shi), Shimabara

Generally completed

Onsen

30 x 390; ENE

Nagasaki Ken, Minami-takaki Gun, Obama Machi

Same as above

Takematau (Shinomura)

50 x 1,350; NNW

Nagasaki Ken, Higashi-sonoki Gun, Takamatsu Cho

50 x 950

Generally completed

Makinohara

60 x 900; NW

Kagoshima Ken, Airs Gun, Shikine Mura

Generally completed

Nagao

(Iwakawakaido)

60 x 1,200; NE

Kagoshima Ken, Kimotsuki Gun, Kasanohara Mura

Generally completed

Yokosuka

Kantatsu

30x600

Ibaragi Ken, Niihari Gun, Ishida Mura

Already established. Runway of the Tsuchiura Air Group

Chart 7

Preparation of Bases for Special Planes Bases for Model 43 Oka

(Yokosuka Naval District Top Secret Operational Order No 496, 20 May 1945)

Name of Base

Catapults

Completion Date

Sheds of Oka Bombs

Completion Date

Izu Peninsula

8

Middle of August

5

Middle of August

20

Middle of September

20

Middle of October

Southern Boso Peninsula

6

Middle of August

Same as above

Same as above

Eastern Boso Peninsula

6

Middle of August

Same as above

Same as above

Vicinity of Tsukuba

6

Middle of September

5

Middle of September

20

Middle of October

20

Middle of November

Miura Peninsula

3

Middle of July

5

Middle of July

10

Middle of November

Vicinity of Oi

6

Middle of October

5

Middle of September

20

Middle of October

Vicinity of Toba

6

Middle of October

Same as above

Same as above

bat men from commanders down to crewmen. Therefore, the High Command exerted efforts to produce as highly effective special attack planes as possible. The following are the orders and results concerning experiments and research on special attack planes:

Front Chief, First Bureau, Naval General Staff, Imperial General Headquarters

To: Chief, Navy affairs Bureau, Navy Ministry

Chief, General Affairs Bureau, Navy Aeronautical Department

Chief, General Affairs Bureau, Navy Technical Department

Request Concerning an Increase in the Effectiveness of Special Attack Planes

In view of the great difference in air strength between the enemy and ourselves and the degree of training of Navy airmen, greater importance should be attached to special attack planes. Judging from past combat experiences and statements of prisoners of war, it is impossible to inflict a fatal blow on large enemy vessels, because the equipment and methods used by the present special attack planes are inadequate for complete penetration. Therefore, it is requested that the following matters be immediately studied in order to increase their effectiveness. 1. It is requested that a test be conducted immediately in order to deliver successful bomb hits below the waterline of enemy vessels by special attacks:

20 May 1915

a. Stern attack

--19--

(Even if the bomb does not hit and explode at the ship's bottom, there is a strong probability that it will reduce mobility by hitting the armorless stem near the water line.)

b. Side attack

2. Method of increasing the approach speed of special attack planes: It is requested that the wings of the special attack planes be removed during the dive in order to achieve a sudden increase in speed and to minimize damage by enemy interception and defensive fire. Furthermore, this will increase the effect of the hits by increasing the approach speed. It is requested that this procedure be applied to the Ki-115 and that measures be taken immediately for their mass production.

3. It is requested that tests of V-head bombs be completed immediately and that they be supplied to the operational forces.

4. Testing of explosive charges to increase bursting effect: It is requested that methods of producing a more powerful bursting effect, to be employed by the special attack plane by loading it with liquid oxygen, hydrogen peroxide or yellow phosphorous, be studied and tested.

5. It is suggested as a method of using these new charges as substitutes for bombs, that the obsolete torpedo air chamber (re-

--20--

move rear part, including the torpedo engine room) be used by filling it with hydrogen peroxide, et cetera.

As requested, tests of explosive charges were held at Takeyama and Kure. The results of these tests are shown on Charts 8 and 9.

A request for testing the effectiveness of special attack planes by using a real warship as a target and catapulting special attack planes from catapults was submitted by the Naval General Staff in late May. It was first decided to use two warships, the Ise and the Hyuga. However, in the test, due to various circumstances, the Aso was decided upon.

Except for the Type 0 Fighter, with a 500 kg bomb, and the land bomber (Francis) with two 800 kg bombs, which had actually been used in combat, there were no other planes tested prior to termination of the war. Even the above, two tests were mainly the result of the efforts of the combat forces.

Surface and underwater special attack weapons: The Japanese Navy, which had long been accustomed to building large vessels and big guns, began to concentrate on the construction of small vessels and craft from the time of the Revised Fifth Replenishment Plan. At the same time attention was shifted to mass production of special attack weapons.

Surface and Underwater Special Attack Weapons Preparation Plan

Apr

May

Jun

Jul

Aug

Sep

Total

Submarines (Small)

2

4

8

13

13

40

KORYU (Midget submarine)

27

33

50

100

150

180

540

--21--

Chart 8

Condensed Report of the Results of Tests at Takeyama Base

Date

Type of Aircraft

Bombs

No. of Bombs

Thickness of Armor Plate

Angle of Incidence

Target Angle

Speed

Results

1

17 Jul

Type 93 Intermediate Trainer

250 kg land bombs

1

12

30

0

55

Penetration (After action of firing assembly)

2

21 Jul

Shiragiku Utility Trainer

250 kg land bombs

2

12

30

0

53

Same as above

3

24 Jul

Type 9 Fighter

500 kg general purpose bombs

1

12

30

0

55

Same as above

4

28 Jul

Shiragiku Utility Trainer

250 kg land bombs

2

8

60

0

55

Ricochet (After action of firing assembly)

5

3 Aug

Shiragiku Utility Trainer

250 kg land bombs

1

8

0

45

55

Penetration (After action of firing assembly)

6

15 Aug

Type 93 Intermediate Trainer

250 kg land bombs

1

8

60

0

80

Same as above

Chart 9

Results of Ko-Go Tests at Kure Navy Yard

Warship Used

Type of Bomb Tested

Installation

Results

1

Aso

(Medium-Class Aircraft Carrier)

(Not completed, had no flight deck Displacement Tonnage at that time was 10,000 tons)

Type A Torpedo Warhead (V-Head)

Angle of incidence, 15 deg on the forelift

Only small holes were Caused on both side plates; operation of the warship was hardly affected

2

Type 4 Torpedo Warhead (V-Head)

On the tower whose height is equal to the distance between the shelter deck and the flight deck (in the center of the warship)

(Angle of incidence, 45 deg)

The spaed remained unchanged and navigation was possible in spite of the damage suffered on the shelter deck and the upper deck

3

500 kg General Purpose Bomb

On the armor deck over the fore magazine room (Angle of incidence, 45 deg)

The armor deck sank and starboard plate was holed 6 m x 12 m

Flooding; 2,070 tons

A

V Bomb (800 kg Oka Model 22)

On the lower deck near the after lift (Angle of incidence 45 deg)

Hole 3 m x 7 m was caused on the armor deck.

There was no flooding in spite of serious damage

5

Sakura

Bomb

(Army)

On top of the tower whose height 1a equal to the distance between the shelter deck and the flight deck. (On the aftermost part of the warship) (Angle of incidence 20 deg)

Hole at the bottom of the warship was 6.9 m x 8 m

Flooding, 150 tons

Summary

1. Effectiveness of the air burst of the Type 4 torpedo head is comparatively small and therefore, its value as a special attack weapon is small.

2. The V bomb had a greater penetration power than does the general purpose bomb. Therefore, it must be prepared immediately and tested for its effectiveness as compared to the general purpose bomb.

3. Although the Sakura bomb might inflict comparatively small damage to a ship, it is recognised that the bomb can inflict fatal damage to a war ship, if it hits, for instance, the magazine room.

4. In general, the penetration bomb can destroy that part of the object in the course of the flame.

However, it does hardly any damage to parts not on this course.

Apr

May

Jun

Jul

Aug

Sep

Total

KAIRYU (Midget submarine)

100

95

105

150

150

150

750

KAITEN (Human torpedo)

73

83

93

To be decided later

249

SHINYO (surface craft)

Model 1

300

600

600

600

600

600

3,450

Model 5

150

However, because of various successive bottlenecks in the execution of the plan, only approximately half of the plan was realized. Actual production was as shown on Chart 10.

The organization and disposition of surface and underwater special attack units for the decisive battle of the Homeland are shown on the following charts:

Chart 11: Table of Organization of Special Attack Squadrons

Chart 12: Chart Showing the Location of Special Attack Bases

Chart 10

Results of Surface and Underwater Special Attack Weapons Preparation

Production

Total

Percentage

April

May

June

Completed

Plan

Completed

Plan

Completed

Plan

Completed

Plan

Submarines (Small)

2

2

2

4

4

6

67

KORYU (Midget submarine)

12

27

12

33

20

50

44

110

40

KAIRYU (Midget submarine)

9

100

42

95

74

105

125

300

42

KAITEN (Human torpedo)

66

73

42

83

51

92

159

249

64

SHINYO (Suicide surface craft)

Type 1

68

300

316

450

284

450

668

1,200

56

Type 5

181

150

167

150

111

150

459

450

102

Chart 11-a

Table of Organisation of Special Attack Squadrons

Force

Vessels

Attack Units

Other Units

Yokosuka Naval

District Force

1st Special

Attack

Squadron

Destroyer Sawakase

Yokosuka Attack Unit

Yokosuka Naval Defense Corps

Frigates Amakusa, Shizaka

11th " "

Frigate No 37

15th " "

Minesweeper No 27

16th " "

Subchasers Nos 42, 47 & 51

18th " "

Light

Minelayer Kamijima

71st " "

7th Special

Attack

Squadron

Minesweeper No 1

12th Attack Unit

Onagawa Naval Defense Corps

Subchasers Nos 33 ft 48

14th " "

17th " "

4th Special

Attack

Squadron

Submarine

Tender Komahashi

13th Attack Unit

Ise Naval

Defense Corps

Frigates Nos 4, 45 & 50

19th " "

Subchasers Nos 14 & 44

Kure Naval District Force

2d Special

Attack

Squadron

Okami Attack Unit

Hikari " "

Hirao " "

Kasado " "

81st " "

8th Special

Attack

Squadron

34th Minesweeper Division

21st Attack Unit

Saeki Air Group

23d " "

Saeki Naval Defense Corps

24th " "

Osaka Guard District Force

6th Special

Attack

Squadron

Frigates Nos 30 & 190 Petrol Boat No 104

22d Attack Unit

Kii Naval

Defense Corps

Chart 11-b

Table of Organization of Special Attack Squadrons

(Cont'd)

Force

Vessels

Attack Units

Other Units

Sasebo Naval District Force

3d Special

Attack

Squadron

Kawadana Attack Unit

31st " "

34th " "

5th Special

Attack

Squadron

Subchaser No 49

32d Attack Unit

33d " "

35th " "

Maizuru Naval District Force

Maizuru Attack Unit

Chinkai Guard District Force

42d Attack Unit

Combined Fleet

10th Special

Attack

Squadron

Submarine HA-109

101st Attack Unit

Submarine HA-111

102d " "

Oura " "

Shozushima Attack Unit

Seventh Fleet

36th Attack Unit

Chart 12-a

Location of Special Attack Bases 15 August 1945

Chart 12-b

Location of Special Attack Bases 15 August 1945

(Cont'd)

Chart 12-c

Location of Special Attack Bases 15 August 1945

(Cont'd)

APPENDIX I

Major Naval Arms and Weapons Produced from January 1944 to Cessation of Hostilities

Appended Chart 1-a

Naval Craft Completed After January 1944 (Number and Displacement)

Type of Naval Craft

Class and Displacement

1944

1945

First Quarter

Second Quarter

Third Quarter

Fourth Quarter

First Quarter

Second Quarter

Third Quarter

Incomplete

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Aircraft Carrier

No 110 Class

62,000

1 62,000

Taiho Class

30,360

1 (TN Number of craft)

30,360 (TN Displacement)

Unryu Class

17,500

2 35,000

1 17,500

1 17,500

Unryu Class

17,460

1 17,460

Hiryu Class

17,260

1 17,260

Ibuki Class

12,500

1 12,500

Monthly total

1 30,360

2 35,000

1 17,500

1 82,000

4 64,720

Quarterly total

1 30,360

2 35,000

2 79,500

4 64,720

Cruiser

Agano Class

6,500

1 6,500

Quarterly total

1 6,500

Destroyer

Yugumo Class

2,040

1 2,040

1 2,040

1 2,040

Akizuki Class

2,700

1 2,700

1 2,700

2 5,400

1 2,700

1 2,700

Matsu Class

1,260

1 1,260

3 3,780

1 1,260

3 3,780

4 5,040

1 1,260

3 3,780

1 1,260

3 3,780

1 1,260

6 7,560

1 1,260

3 3,780

1 1,260

4 5,040

Monthly total

1 2,040

2 4,740

1 1,260

2 4,740

3 3,780

1 1,260

3 3,780

4 5,040

1 1,260

3 3,780

3 6,660

4 6,480

1 1,260

6 7,560

2 3,960

3 3,780

1 1,260

4 5,040

Quarterly total

3 6,780

6 9,780

8 10,080

7 11,700

11 15,300

6 9,000

4 5,040

Submarine

I-400 Class

3,430

1 3,430

1 3,340

1 3,430

1 3,430

I-351 Class

2,650

1 2,650

1 2,650

I-13 Class

2,400

1 2,400

1 2,400

1 2,400

I-1 Class

2,390

1 2,390

I-16 Class

2,180

1 2,180

1 2,180

1 2,180

I-15 Class

1,950

1 1,950

Appended Chart 1-b (Cont'd)

Naval Craft Completed After January 1944 (Number and Displacement)

Type of Naval Craft

Class and Displacement

1944

1945

Incomplete

First Quarter

Second Quarter_

Third Quarter

Fourth Quarter

First Quarter

Second Quarter

Third Quarter

Jan

Feb

Mar

V

Mar

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Submarine

I-52 Class

2,100

1 2,100

1 2,100

I-54 Class

1,950

1 1,950

1 1,950

1 1,950

I-361 Class

1,470

2 2,940

1 1,470

1 1,470

4 5,880

1 1,470

2 2,940

I-372 Class

1,660

1 1,660

1 1,660

1 1,660

I-201 Class

1,000

2 2,000

1 1,000

5 5,000

RO-35 Class

965

2 1,930

1 965

1 965

1 965

1 965

1 965

1 965

RO-100 Class

429

2 858

HA-101 Class

370

1 370

3 1,110

3 1,110

1 370

1 370

1 370

2 740

HA-201 Class

320

2 640

2 640

1 320

5 1,600

22 7,040

I-12 Class

2,200

1 2,200

Monthly total

5 4,738

3 5,245

2 2,915

1 2,100

4 6,105

2 3,420

3 4,615

4 5,880

4 6,565

2 2,940

3 2,995

5 6,940

2 6,080

5 3,110

2 2,770

1 1,660

3 1,010

3 1,040

3 4,120

5 1,600

34 25,310

Quarterly total

10 12,898

7 11,625

11 17,060

10 12,875

9 11,960

7 4,310

8 5,720

34 25,310

Minelayer

Minomo Class

3,000

1 3,000

Quarterly total

1 3,000

Frigate

Etorofu Class

870

1 870

Mikura Class

940

1 940

2 1,880

1 940

2 1,880

2 1,880

2 1,880

1 940

1 940

3 2,820

5 4,700

3 2,820

3 2,820

4 3,760

4 3,760

1 940

4 3,760

No 1 Class

750

2 1,500

4 3,000

4 3,000

4 3,000

3 2,250

4 3,000

5 3,750

5 3,750

5 3,750

2 1,500

3 2,250

2 1,500

3 2,250

4 3,000

1 750

2 1,500

4 3,000

No 2 Class

740

3 2,220

9 6,660

1 740

2 1,480

2 1,480

5 3,700

5 3,700

6 4,440

4 2,960

7 5,180

3 2,220

5 3,700

6 4,440

2 1,480

2 1,480

1 740

5 3,700

Monthly total

1 940

8 6,470

13 9,660

6 4,680

4 3,360

4 3,360

6 4,480

9 6,890

10 7,640

14 11,010

9 6,710

17 13,630

8 6,540

11 8,770

12 9,700

9 7,490

4 3,000

1 750

5 3,920

1

13 10,460

Quarterly total

22 17,070

14 11,400

25 19,410

40 31,350

31 25,010

14 11,240

6 4,660

13 10,460

Naval Transport

No 1 Class (TN APDI)

1,500

1 1,500

3 4,500

3 4,500

3 4,500

3 4,500

3 4,500

2 3,000

1 1,500

1 1,500

1 1,500

1 1,500

No 101 Class (TN LSMI)

890

2 1,780

4 3,560

2 1,780

3 2,670

4 3,560

4 3,560

3 2,670

12 10,680

5 4,450

3 2,670

1 890

3 2,670

1 890

1 890

1 890

4 3,560

Appended Chart 1-b (Cont'd)

Naval Craft Completed After January 1944 (Number and Displacement)

Type of Naval Craft

Class and Displacement

1944

1945

Incomplete

First Quarter

Second Quarter

Third Quarter

Fourth Quarter

First Quarter

Second Quarter

Third Quarter

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Naval Transport

Monthly total

2 1,780

5 5,060

2 1,780

3 2,670

7 8,060

4 3,560

6 7,170

15 15,180

5 4,450

6 7,170

4 5,390

3 2,670

2 3,000

1 890

2 2,390

1 1,500

2 2,390

5 5,060

Quarterly total

7 6,840

12 12,510

25 25,910

15 17,010

6 6,560

3 3,890

2 2,390

5 5,060

Minesweeper

No 19 Class

630

1 630

2 1,260

1 630

1 630

Quarterly total

1 630

3 1,890

1 630

Subchaser

No 13 Class

440

2 880

3 1,320

1 440

1 440

1 440

1 440

Quarterly total

5 2,200

2 880

1 440

1 440

Light Minelayer

Ajiro Class

720

1 720

Kamishima Class

766

1 766

1 766

Monthly total

1 720

1 766

1 766

Quarterly total

1 720

1 766

1 766

Special Duty Ship

Hario Class (AO)

18,500

1 18,500

Ohama Class (target ship)

2,670

1 2,670

1 2,670

Monthly total

1 18,500

1 2,670

1 2,670

Quarterly total

1 18,500

1 2,670

1 2,670

Auxiliary Patrol Vessel

No 1 Class

238

2 476

4 952

2 476

6 1,428

4 952

5 1,190

4 952

26 6,188

Quarterly total

6 1,428

12 2,855

9 2,142

26 6,188

Auxiliary Subchaser

No 1 Class

130

4 520

8 1,040

9 1,170

6 780

9 1,170

10 1,300

13 1,690

12 1,560

10 1,300

11 1,430

14 1,820

910

5 650

Quarterly total

21 2,730

25 3,250

32 4,160

Monthly total

12 7,078

23 17,205

35 55,225

16 10,600

25 19,745

28 20,990

30 17,795

36 60,280

43 35,725

35 39,030

37 90,975

37 52,030

23 25,090

21 16,616

25 21,872

16 15,976

17 10,718

9 4,602

16 12,386

11 6,292

88 120,214

Quarterly total

70 79,508

69 51,335

109 113,800

109 182,035

69 63,578

42 31,296

27 18,678

88 120,214

Remarks: The naval craft listed as incomplete refer to those not yet completed at the end of war and also those whose construction was suspended during the war.

Appended Chart 2

Transports and Freighters Completed After January 1944

Year

Month

Quarter

Freighter

Tanker

Others

Monthly total

Quarterly total

No

Tonnage

No

Tonnage

No

Tonnage

No

Tonnage

No

Tonnage

1944

Jan

First Quarter

28

56,520

11

36,470

3

15,250

42

108,240

203

514,840

Feb

45

89,100

13

38,370

58

127,470

Mar

72

183,430

27

89,570

4

6,130

103

279,130

Apr

Second Quarter

34

72,590

8

6,960

42

79,550

161

370,610

May

40

82,180

19

61,110

3

2,000

62

145,290

Jun

40

97,650

17

48,120

57

145,770

Jul

Third Quarter

33

50,620

17

55,270

3

2,000

53

107,890

180

398,470

Aug

33

38,820

24

71,890

57

110,710

Sep

40

52,050

29

127,320

1

500

70

179,870

Oct

Fourth Quarter

40

48,830

23

97,200

1

500

64

146,530

189

418,990

Nov

40

59,720

24

77,480

1

900

65

138,100

Dee

41

76,810

18

57,050

1

500

60

134,360

1945

Jan

First Quarter

31

63,170

16

51,000

3

10,500

50

124,670

130

386,320

Feb

36

101,930

12

50,920

48

152,850

Mar

27

85,080

3

13,720

2

10,000

32

108,800

Apr

Second Quarter

12

23,180

1

500

13

23,680

41

128,550

May

19

63,470

1

500

20

63,970

Jun

8

40,900

8

40,900

Jul

Third Quarter

11

36,580

11

36,580

18

56,401

Aug

7

19,821

7

19,821

Appended Chart 3-a

Aircraft Produced January 1944 - August 1945

Month Year

1944

Item

Type of Aircraft

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Standard Planes

Carrier-borne fighters

1

363

269

362

339

327

300

278

367

224

994

966

889

Interceptors

2

35

67

75

117

58

116

127

117

125

177

291

369

Night fighters

3

25

18

18

35

40

40

27

35

40

61

115

102

Carrier-borne bombers

4

140

H7

141

125

133

118

107

106

122

428

376

335

Carrier-borne attack bombers

5

30

25

39

36

36

57

79

85

76

94

129

240

Land-based reconnaissance planes

6

1

2

6

6

0

1

4

8

19

9

7

31

Land-based bombers

7

11

20

35

46

46

51

47

48

69

66

143

164

Land-based attack bombers

8

53

46

50

73

70

79

89

85

91

H9

222

265

Patrol planes

9

1

1

2

1

2

3

3

3

3

4

6

9

Land-based transport planes

10

8

14

15

3

3

17

H

16

19

37

23

49

Seaplane fighters

11

9

10

10

0

0

0

0

0

0

29

0

0

Reconnaissance seaplanes

12

51

49

51

53

53

62

52

59

40

151

168

151

Appended Chart 3-b

Aircraft Produced January 1944 - August 1945

(Cont'd)

1944

1945

Japanese Designation of Aircraft (Factory)

Oct

Nov

Dec

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

1

339

360

268

251

167

247

267

285

208

153

101

Type-0 fighter (Nakajima and Mitsubishi)

967

665

760

254

2

129

121

95

89

97

140

128

101

56

44

8

Shiden (Kawanishi and Showa).

Raiden (Mitsubishi)

345

326

285

52

3

23

0

0

0

0

0

0

0

0

0

0

Gekko (Nakajima)

23

0

0

0

4

116

133

150

115

98

101

96

46

67

33

4

Suisei (Aichi and 11th Naval Air Depot) Type-99 (Aichi and Showa)

399

314

209

37

5

96

87

60

75

83

94

65

12

42

13

1

Tenzan (Nakajima). Ryusei (Aichi and 21st Naval Air Depot)

243

252

119

14

6

25

26

25

30

38

64

60

58

47

35

4

Saiun (Nakajima)

76

132

165

39

7

75

88

84

90

52

52

63

64

53

40

20

Ginga (Nakajima and Kawanishi)

247

194

180

60

8

109

108

60

55

60

50

65

31

25

1

0

Type-1 (Mitsubishi)

277

165

121

1

9

8

11

14

16

11

13

13

15

12

12

6

Tokai (Kyushu)

33

40

40

18

10

20

16

17

19

9

21

15

14

3

7

1

Type-0 (Showa)

53

49

32

8

11

0

0

0

0

0

0

0

0

0

0

0

Kyofu (Kawanishi)

0

0

0

0

12

61

70

73

49

47

32

22

16

11

4

4

Type-0 (Kyushu) Zuiun (Nippon Hikoki and Aichi)

204

128

49

8

Appended Chart 3-c

Aircraft Produced January 1944 - August 1945

(Cont'd)

Item

Year Month

1944

Type of Aircraft

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Standard Planes

Observation planes

1

50

40

35

30

35

30

15

6

0

125

95

21

Seaplane bombers

2

0

1

0

0

0

2

1

1

1

1

2

3

Flying boats

3

9

9

10

9

8

8

5

3

3

28

25

11

Total of combat aircrafts

4

786

718

849

873

811

884

848

939

852

2,353

2,568

2,639

Trainer

5

212

223

281

297

281

278

262

212

147

716

856

621

Total

6

998

941

1,130

1,170

1,092

1,152

1,110

1,151

999

3,069

3,424

3,260

Special-Type Planes

Oka, Model 11

7

10

10

Oka,

Model 22

8

Shusui

9

Kikka

10

Total

11

10

10

Grand Total

12

998

941

1,130

1,170

1,092

1,162

1,110

1,151

1,009

3,069

3,424

3,270

 Appended Chart 3-d

Aircraft Produced January 1944 - August 1945 (Cont'd)

1945

Japanese Designation of aircraft (Factory)

Oct

Nov

Dec

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

1

0

0

0

0

0

0

0

0

0

0

0

Type-0 (21st Naval Air depot)

0

0

0

0

2

2

1

1

1

2

2

2

4

2

3

0

Seiran (Aichi)

4

5

8

3

3

3

4

6

4

2

2

3

0

0

0

0

Type-2, Soku (Kawanishi)

13

8

3

0

4

1,006

1,025

853

794

666

818

799

646

526

345

149

2,884

2,278

1,971

494

5

153

123

132

157

154

158

86

89

72

63

68

Type-0 training (Hitachi) Shiragiku (Kyushu) Type-93 intermediate trainer (Fuki and Nippon Hikoki)

408

469

247

131

6

1,159

1,148

985

951

820

976

885

735

598

408

217

3,292

2,747

2,218

625

7

50

95

93

160

197

150

(1st Air Technical Depot)

238

507

8

50

(1st Air Technical Depot)

50

9

1

4

(Mitsubishi and Nippon Hikoki)

1

4

10

1

(Nakajima)

0

1

11

50

95

93

160

197

151

51

4

238

508

51

4

12

1,209

1,243

1,078

1,111

1,017

1,127

885

735

649

412

217

3,530

3,255

2,269

629

Appended Chart 4A-a

Guns and Ammunition Produced January 1944 - August 1945

Weapons

and Ammunition

Type of Guns

Caliber

1944

First Quarter

Jan

Feb

Mar

Guns

Flat

220mm

1

3

2

1

6

140mm

1

1

1

2

3

127mm

6

6

6

3

18

200mm short barrel and 120mm

33

51

46

4

130

Miscellaneous

5

2

3

2

7

Total

6

45

63

56

164

Dual

purpose

guns

127mm

7

30

30

30

90

120mm

8

62

81

95

238

100mm

9

8

12

2

22

80mm

10

8

2

8

18

Total

11

108

125

135

Total

12

153

188

191

532

Automatic

cannon and Machine gun

Machine guns

30mm

13

15

5

25

Appended Chart 4A-b

Guns and Ammunition Produced January 1944 - August 1945

(Cont'd)

1944

Second Quarter

Third

Quarter

Fourth Quarter

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

1

2

1

2

1

2

1

1

1

1

5

4

3

2

1

1

1

1

1

1

1

1

1

3

3

3

3

1

1

0

0

1

0

0

1

0

2

1

1

4

50

50

60

60

60

60

50

40

30

150

180

120

5

3

3

3

3

3

3

3

3

3

9

6

56

56

65

67

65

55

46

35

169

197

136

7

30

30

30

30

30

30

30

30

20

90

90

80

8

100

120

150

140

180

200

200

180

130

370

520

510

9

4

4

4

4

4

3

4

4

4

12

11

12

10

5

6

5

5

5

5

5

5

5

16

15

15

11

139

160

189

179

219

238

239

219

159

488

636

617

12

196

216

245

244

286

303

294

265

194

657

833

753

13

15

20

0

10

15

20

0

25

15

35

45

40

Appended Chart 4A-c

Guns and Ammunition Produced January 1944 - August 1945

(Cont'd)

1945

First Quarter

Second Quarter

Third Quarter

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

1

1

1

1

0

0

0

0

0

3

0

0

2

1

1

1

0

0

0

0

0

3

0

c

3

0

1

0

0

0

0

0

0

1

0

c

4

30

30

20

20

10

5

5

0

80

35

5

5

3

3

3

1

1

1

0

0

9

3

0

6

35

36

25

21

11

6

5

0

96

38

5

7

15

15

10

10

15

10

10

5

40

35

15

8

110

100

90

80

60

40

5

0

300

180

5

9

4

1

0

4

3

2

1

0

5

9

1

10

5

5

5

4

3

2

1

0

15

9

1

11

134

121

105

98

81

54

17

5

360

233

22

0

12

169

157

130

119

92

60

22

5

456

271

27

13

70

110

350

500

350

460

500

140

530

1,310

640

Appended Chart 4A-d

Guns and Ammunition Produced January 1944 - August 1945

(Cont'd)

Weapons

and Ammunition

Type of Guns

Caliber

1944

First Quarter

Jan

Feb

Mar

Automatic

cannon

and

machine guns

Machine guns

25mm

1

800

1,000

1,000

2,800

20mm

2

770

1,195

1,710

3,675

13mm

3

600

740

780

2,120

7.9mm and 7.7mm

4

1,475

1,710

1,825

5,010

Total

5

3,660

4,650

5,320

13,630

Ammunitions

For flat guns

20mm and above

6

1,000

1,000

1,000

3,000

155mm and below

7

21,000

20,000

20,000

61,000

Total

8

22,000

21,000

21,000

64,000

For dual purpose gun

9

30,000

30,000

30,000

90,000

Total for flat and dual purpose guns

10

52,000

51,000

51,000

154,000

For automatic cannon and machine gun (thousand of rounds)

11

10,860

12,008

15,395

38,263

Appended Chart 4A-e

Guns and Ammunition Produced January - August 1945

(Cont'd)

1944

Second Quarter

Third Quarter

Fourth Quarter

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

1

1,500

1,700

1,700

2,000

2,000

2,000

2,200

2,200

2,000

4,900

6,000

6,200

2

1,240

1,520

2,340

2,340

3,375

3,080

3,660

3,830

3,490

5,100

8,795

10,980

3

900

1,000

1,150

1,080

1,300

1,320

1,455

1,605

1,590

3,050

3,700

4,650

4

1,430

1,545

1,550

1,685

1,265

1,210

1,500

1,195

1,030

4,525

4,160

3,725

5

5,085

5,785

6,740

7,115

7,955

7,630

8,815

8,655

8,125

17,610

22,700

25,595

6

1,000

1,200

800

500

500

500

500

0

0

3,000

1,500

500

7

15,000

10,000

10,000

5,000

5,000

5,000

3,000

2,000

0

35,000

15,000

5,000

8

16,000

11,200

10,000

5,500

5,500

5,500

3,500

2,000

0

38,000

16,500

5,500

9

30,000

40,000

40,000

40,000

40,000

50,000

50,000

60,000

60,000

110,000

130,000

170,00

10

45,000

51,200

50,800

45,500

45,500

55,500

53,500

62,000

60,000

148,000

146,500

175,500

11

13,543

13,390

12,306

12,728

12,210

11,193

11,391

11,466

10,419

39,239

36,131

33,276

Appended Chart 4A-f

Guns and Ammunition Produced January 1944 - August 1945

(Cont'd)

1945

First

Quarter

Second Quarter

Third Quarter

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

1

1,800

1,600

500

800

800

500

400

100

3,900

2,100

500

2

3,195

1,695

1,855

1,405

1,435

1,625

785

400

6,745

4,465

1,185

3

1,755

2,040

1,905

1,685

1,545

1,330

1,205

375

5,700

4,560

1,580

4

1,140

805

1,245

1,010

1,110

785

740

310

3,190

2,905

1,050

5

7,960

6,250

5,855

5,400

5,240

4,700

3,630

1,325

20,065

15,340

4,955

6

0

0

0

0

0

0

0

0

0

0

0

7

0

0

0

0

0

0

0

0

0

0

0

6

0

0

0

0

0

0

0

0

0

0

0

9

40,000

35,000

10,000

30,000

20,000

20,000

10,000

5,000

85,000

70,000

15,000

10

40,000

35,000

10,000

30,000

20,000

20,000

10,000

5,000

85,000

70,000

15,000

11

10,068

10,114

11,441

11,240

11,087

8,013

5,738

3,446

31,623

30,340

9,184

Remarks:

The guns listed here are those produced for naval craft, aircraft and naval land bases and do not include guns for land mobile combat use. However, the automatic cannon and machine guns and the ammunition to include those for land mobile combat use.

Appended Chart 4B

Land Mobile Combat Weapons Produced January - 1944 - August 1945

Year

1944

1945

Month, Quarter

Jan

to

Dec

Jan

to

Mar

Second Quarter

Jul to Aug

Gun and Ammunition

Apr

May

Jun

120mm gun, short barrel, for land mobile combat

Unknown

Unknown

5

29

0

Unknown

34

Ammunition for 120mm short barrel, for land mobile combat

"

"

5,800

4,700

3,000

"

13,500

80mm mortar

"

"

393

345

200

"

938

Ammunition for 80mm mortar

"

"

37,000

37,000

70,000

"

144,000

200mm rocket gun

"

"

50

10

190

"

250

100mm antitank gun (rocket type)

"

"

0

5

50

"

55

80mm antitank gun (rocket type)

"

"

210

60

345

"

615

Ordinary rocket shell

"

"

2,500

3,400

5,500

"

11,400

Antitank rocket shell

"

"

1,000

500

500

"

2,000

Hand grenade

"

"

15,000

85,000

300,000

"

400,000

Remarks:

1. The weapons listed here are these for land mobile combat.

2. Since records for months other than April, May and June of 1945 are not available, nothing definite is known.

3. Land mobile combat weapons, other than those listed here, are chiefly rifles and pistols transferred from the Army, but their number is unknown because of a lack of records.

4. Re vehicular weapons, tanks were chiefly transferred from the Army and the rest were appropriated by the Munitions Ministry. Their number also is unknown.

Appended Chart 5

Gunpowder Produced After January 1944 (Quantity in Kilograms)

Year and Month

Quarter

Powder for Guns

Powder for Machine Guns

Propellants

Explosives

Total

1944

Jan

First Quarter

464

1,351

233

746

8

25

1,937

6,187

2,642

8,309

Feb

474

233

7

2,061

2,775

Mar

413

280

10

2,189

2,892

Apr

Second Quarter

452

1,426

347

1,002

59

194

2,156

6,803

3,014

9,425

May

487

335

65

2,297

3,184

Jun

487

320

70

2,350

3,227

Jul

Third Quarter

487

1,423

319

1,000

70

249

2,451

7,512

3,327

10,184

Aug

466

330

89

2,412

3,297

Sep

470

351

90

2,649

3,560

Oct

Fourth Quarter

444

1,318

355

1,079

116

336

2,632

7,902

3,5,47

10,635

Nov

452

354

110

2,697

3,613

Dec

422

370

110

2,573

3,475

1945

Jan

First Quarter

422

1,286

420

1,220

145

508

2,489

7,789

3,476

10,803

Feb

422

420

164

2,520

3,526

Mar

442

380

199

2,780

3,801

Apr

Second Quarter

317

930

155

688

262

818

1,907

6,220

2,641

8,656

May

319

236

279

2,538

3,372

Jun

294

297

277

1,775

2,643

Jul

Third Quarter

229

343

142

193

170

237

1,281

1,927

1,822

2,700

Aug

114

51

67

646

878

Appended Chart 6

Fuel Produced After January 1944

Year

and Month

Item

Aviation Gasoline

Heavy Oil

Unit

(Kilograms)

(Tons)

Quarter

1944 Jan

First Quarter

18,000

56,000

29,000

83,000

Feb

21,000

29,000

Mar

17,000

25,000

Apr

Second Quarter

20,000

60,000

25,000

80,000

May

20,000

27,000

Jun

20,000

28,000

Jul

Third Quarter

19,000

49,000

28,000

75,000

Aug

15,000

25,000

Sep

15,000

22,000

Oct

Fourth Quarter

15,000

49,000

22,000

71,000

Nov

19,000

29,000

Dee

15,000

20,000

1945 Jan

First Quarter

14,000

34,000

18,000

58,000

Feb

13,000

19,000

Mar

7,000

21,000

Apr

Second Quarter

8,000

17,000

20,000

59,000

May

3,000

19,000

Jun

6,000

20,000

Jul

Third Quarter

7,000

10,000

11,000

15,000

Aug

3,000

4,000

Appendix II

Agreement Between the Army and the Navy Concerning War Preparations for the First Half of Fiscal Year 1945

Army General Staff

Navy General Staff

1 April 1945

Deputy Chief, Army General Staff

Vice-Chief, Navy General Staff

I, General Principles

The war preparations of the Army and the Navy for the first half of the fiscal year 1945 will be accomplished in accordance with the following principles:

1. Priority will be given to the equipment of the Air Forces and the Special Attack Forces. Of the Army land forces (operational forces, including the 40 newly-organized divisions) and the Navy forces (excluding Air Force and Special Attack Forces), those which can be relied upon to display fighting power to repel the enemy during the decisive battle for the Homeland will be provided promptly with sufficient equipment. War preparations for the defense of surface communications routes will be restricted to a minimum, while other preparations will be executed in consonance with national power and within a limit which will not affect major war preparations.

2. Efforts will be made by both the army and the Navy to cooperate in their war preparations. In exchanging assistance, the Array will facilitate the Navy's procurement of aircraft and special underwater attack

weapons for attacking enemy task forces. The Navy will assist the Army in its procurement of aircraft and ground weapons to be used in the local air defense of the Homeland.

3. The Supreme Command will maintain close contact with the Government and extend all-out support and cooperation to the latter in concentrating the resources of the entire nation for war purposes, as well as in building up such war preparations.

U. The planning of Array and Navy war preparations, (items, quantities, priority, et cetera) will be based on the principles enumerated herein and implementation of such plans will be carried out with a view to adequate realization of such plans.

II. Essentials of the Goal for Army and Navy War Preparations

1. The order of priority in war preparations by the Army and Navy will be as follows:

a. Aircraft and special attack weapons

(1) Aircraft and special air attack weapons. The position on the priority list to be determined separately.

(2) Underwater and special surface attack craft.

(a) Koryu midget submarines and small submarines.

(b) Kairyu midget submarines.

(c) Kaiten human torpedoes.

(d) Shin-yo crash boats.

(3) A minimum number of simple base installations required for operating the above.

--ii--

b. Ground weapons.

(1) Antitank weapons.

(2) Weapons for use against heavy weapons, landing craft and large caliber machine guns.

(3) Close-range automatic weapons and anti-aircraft guns.

(4) A minimum number of simple ground combat fortifications

required for operating the above.

c. Naval craft and weapons for severing the enemy's rear lines and for protecting friendly surface communications lines.

(1) Submarines.

(2) Light minelayers and mines.

(3) Coastal defense craft and depth charges. (4) Frigates.

d. Transports

(1) Navy transports.

(2) Large landing barges.

e. Fortifications and installations

(1) Base for general aircraft and special attack aircraft.

(2) General preparations for land combat.

f. Other items (clothing, materiel, medical and veterinary

supplies)

Minimum requirements proportionate to Army and Navy strength estimated for September 1945.

To secure the necessary provisions, every possible measure

--iii--

will be taken with the nation's food supply taken into consideration. The Army and Navy will collaborate in providing various types of fuel and ammunition in the maximum quantity and in such proportion as to meet the requirements of the different weapons. Maximum efforts will be made in making preparations for chemical warfare. The essentials of this measure will be prescribed in a separate agreement.

2. Essentials concerning procurement and distribution of the principal weapons to the Army and the Navy for the first half of fiscal year 1945 will be determined in accordance with Charts 1 through 7.

--iv--

Chart 1-a

The Number of Aircraft to be Made Available During the First Half of Fiscal Year 1945

Outline of Plan

1. In procuring aircraft, the Army will give top priority to those planes which can be used for attacking enemy vessels, especially transports, and for defending strategic points of the Homeland; the Navy will place too greatest emphasis upon the procurement of those planes which can be used against hostile carrier task forces for the retention of air and sea superiority.

2. Both the Army and the Nary will convert all their planes into special attack planes, procure high priority aircraft and make every effort to ready the various types of aircraft by the middle of the current fiscal year.

3. To meet the minimum operational requirements, the any and the Navy will each procure more than 1,200 front-line planes a month. They will cooperate with each other to facilitate dispersion and transfer underground production facilities.

Classification

Type of aircraft

Minimum Requirements

Production Goal

Army Aircraft

Fighter

Type I fighter

1,390

1,600

Type IV fighter

2,500

3,000

KI-100 fighter

1,200

1,500

KI-102 fighter**

300

500

Type III fighter

300

Total

5,390

6,900

Bomber

Type IV bomber

700

1,200

KI-74 bomber

50

150

Total

750

1,350

Hq Recon Plane

Type 100 Hq racon plane

500

800

Transport Plane

KI-54 (or KI-110) transport plane

100

150

Chart 1-b

The Number of Aircraft to be Made Available Daring the First Half of Fiscal Year

(Cont'd)

Classification

Type of Aircraft

Minimum Requirement

Production Goal

Army Aircraft

Transport Plane

Type 100 transport plane

100

KI-105 transport plane

50

Total

100

150

Trainer

KI-54 (or KI-110) trainer

100

Type II advanced trainer

300

Type IV trainer

250

Total

650

Grand Total

6,740

10,000

Navy Aircraft)

Fighter

Shiden-Kai

2,400

2,400

Zero fighter

1,800

2,700

Kaiden-Kai

600

Saiun

300

300

Ginga

100

100

Total

4,600

6,100

Reconnaissance Plane Saiun

850

850

Attack Plane

Ginga

700

700

Ryusei

300

300

Renzan

50

100

Total

1,050

1,100

Patrol Plane

Type I land-based attack plane***

240

250

Tokai

250

Total

500

Chart 1-c

The Number of aircraft to be Made Available During the First Half of Fiscal Year 1945

(Cont'd)

Classification

Type of Aircraft

Minimum Requirements

Production Goal

Navy

Aircraft

Sea Reconnaissance Plane "Seiran"

80

Type I Transport Plane

320

Type Zero Transport Plane

Trainer

Land-based medium trainer

200

Utility trainer

200

Zero training fighter

350

Type 99 training bomber

100

Tokai trainer

200

Total

1,050

Grand Total

6,740

10,000

Notes: * Number of planes to be procured by all means. Most of the planes to be produced at dispersed, underground facilities.

** Types of KI - 202 fighters that must be acquired by any means are the Type A and C.

*** Type I land-based attack planes will also be used as torpedo bombers.

Chart 2-a

List of Special Attack Weapons to be Produced Daring the First Half of 1945 Fiscal Year

Weapons

Apr

May

Jun

Jul

Aug

Sep

Total

Responsibility for Procurement (The one marked "*" will be mainly responsible)

Remarks

"KI" 115 Special Attack Plane

50

150

300

400

500

600

2,000

Army

Special Type Plane

2,000

Navy

Oka

300

300

300

300

300

300

1,800

Navy

Koryu Midget Submarine

35

35

50

100

150

180

540

Navy

Kairyu Midget Submarine

100

120

130

150

200

200

900

Navy

Maximum efforts will be made to increase production

Kaiten Human Torpedo

100

100

100

110

120

120

650

Navy

Small Submarine

1

5

8

13

13

40

Navy

Shusui

100

150

200

200

250

300

1,200

*Army Navy

To be allocated equally to the Army and the Navy

Chart 2-b

Weapons

Apr

May

Jun

Jul

Aug

Sep

Total

Responsibility for Procurement (The one marked "*" will be mainly responsible)

Remarks

Shinyo Navy Crash Boat

600

600

600

600

600

600

3,600

Army *Navy

Maruhachi Army Crash Boat

500

500

1,000

1,000

3,000

Army

Fu Go Bomb carrying Balloon

1,000

1,000

1,000

3,000

Army

Notes 

1. In addition to the weapons mentioned in this table, 10,000 "Ke" rocket bombs, 1,000 "I Go" bombs and 300 "Kikka" suicide attack planes are scheduled to be procured during the first half of the current fiscal year. But the decision relative to their procurement will depend upon the results of research and examination.

2. Procurement of other weapons now under consideration will be determined and added to this table after the research results are made available.

Chart 3-a

Quantity of Land Combat Weapons to be Produced During the First Half of Fiscal Year 1945

Part 1. Firearms and Guns

Classification of Weapons

Quantity to be Procured

Distribution

Responsibility for Procurement (The one marked "*" will be mainly responsible)

Model 99 Rifle

540,000

Army

440,000

* Army

Navy

100,000

Navy

Sub-machine Gun

6,200

Army

Amy

Pistol

26,000

Army

19,000

Army

24,000

Navy

7,000

Navy

2,000

Heavy Grenade Discharger

20,900

Army

18,000

Amy

18,000

Navy

2,500

Navy

2,500

Light Machine Gun

10,300

Army

Amy

Heavy Machine Gun

4,200

Army

3,500

Amy

3,000

Navy

700

Navy

1,200

Battalion Gun

1,050

Army

Army

"Rota" Rocket Launcher

23,500

Army

13,500

Army

6,000 (70 mm)

Navy

10,000

Navy

17,500 (100mm, 80mm)

47mm antitank Gun

325

Amy

Army

105mm Recoilless Gun

120

Amy

Army

Type 41 Mountain Gun

230

Amy

Army

Type 94 Mountain Gun

130

Amy

Army

Field Gun (Models 90 & 95)

38

Amy

Army

150mm Cannon, 150mm Howitzer

27

Army

Army

Chart 3-b

Quantity of Land Combat Weapons to be Produced During the First Half of Fiscal Year 1945

(Cont'd)

Classification of Weapons

Quantity to be Procured

Distribution

Responsibility of Procurement (The one marked "*" will be mainly responsible)

100mm Howitzer, 100mm Cannon

54

Army

Army

120mm Mortar

720

Army

Army

120mm Short Flat-trajectory Gun

800

Army

400

Navy

Navy

400

80mm Mortar

10,000

Army

5,000

Navy

Navy

5,000

Rocket Gun

4,300

Any

2,300

Army

(120 200mm guns and 180 400mm guns)

Navy

2,000

Navy

(4,000 200mm or 120 mm guns)

Rocket Bomb Launcher

10,000

Army

1,000

Navy

Production goal will be set at 200,000

Navy

9,000

Army

Model 98 Grenade Discharger

3,000

Army

Army

Tanks

300

Army

Army

Self -mobile powered Gun

310

Army

270

Army

270

Navy

40

Navy

40

Part 2. Close-Quarter Combat Weapons

Classification

Quantity

Distribution

Responsibility for Procurement

Flame Thrower

2,400

Army

2,100

Army

2,100

Navy

300

Navy

300

Chart 3-c

Quantity of Land Combat Weapons to be Produced During the First Half of Fiscal Year 1945 (Cont'd)

Classification

Quantity

Distribution

Responsibility for Procurement

Antitank Mine

40,000

(5-kg hemispherical)

Army

Army

(2-kg conical)

(type 3 hand mine)

Yardstick Mine

200,000

Army

100,000

Amy

90,000

Navy

100,000

Navy

110,000

Small-type Mine (Assault)

150,000

Navy

150,000

Navy

Conical Hand Mine

100,000

Army

50,000

Navy

Navy

50,000

Hand Grenade

500,000

Amy

250,000

Amy

125,000

Navy

250,000

Navy

375,000

Molotov Cocktail Incendiary (Smoke) Grenade

300,000

Army

180,000

Amy

180,000

Navy

120,000

Navy

120,000

Part 3. Land Transport Weapons

Classification

Quantity

Distribution

Responsibility for Procurement

Tractor

210

Amy

Amy

Armored Troop Carrier

350

Amy

Amy

Track

6,100

Army and Navy To be fixed according to the else of the ground force

Army

5.100

Navy

■avy

1,000

Chart 3-d

Quantity of Land Combat Weapons to be Produced During the First Half of Fiscal Year 1945 (Cont'd)

Classification of Weapons

Quantity to be Procured

Distribution

Responsibility for Procurement

Amphibious Motor Transport

270

Army

Army

Small-type Track

1,100

Army and Navy

To be fixed according to the size of the ground force

Army

100

Navy

1,000

Trailer

620

Army

Army

Army Transport Car

To be determined separately

Army and Navy

To be fixed according to the size of the ground force

Army

3,000

Navy

To be determined separately

Carts

To be determined separately

Same as above

Army

3,600

Navy

To be determined separately

Part 4. Simple Weapons

To be fixed separately.

Remark: Distribution of ground weapons to the Army and the Navy will be made through a separate channel in order to best meet the war situation and will be based on practical consideration of the ground warfare of the Army and the Navy.

Chart 4-a

Production of Vessels During the First Half of Fiscal Year 1945 (For Escort, Transportation and Traffic Interruption Warfare)

Classification

Completion Expected During the First Half

Maintenance and Distribution

Destroyers

Tei

10

Navy

Submarines

Ko

2

Tei

1

Special

2

Supply

1

High speed

4

Coast Defense Ship's

Ko

20

Hei

Tei

Navy Transports

1st class

4

Navy and Army

2d class SB Type Landing craft

9

Bombardment Target Ship

1

Navy

Minelayer and Concurrently Target Ships

2

Navy

Chart 4-b

Production of Vessels During the First Half of Fiscal Year 1945 (For Escort, Transportation and Traffic Interruption Warfare)

Cont'd

Classification

Completion Expected During the First Half

Maintenance and Distribution

Minelayers

6

Including 4 converted merchant vessels

Coast Defense Boats

Ko

6

Navy

Otsu

18

Special Patrol Boats

40

Large Landing Barges

Special

30

Army

Steel

1,350

Army 900, Navy 450

Wood

1,850

Army 900, Navy 900

Amphibious

30

Navy

Engined Barges

360

Army

Small Transport Barges

400

Folding Boats

600

Type 1 Submersible Transport Craft

30

Remarks: Naval transports, submersible transports and barges shall be employed jointly by the Army and the Navy.

Chart 5-a

Antiaircraft Equipment to be Produced in the First Half of 1945 Fiscal Year

Classification

Quantity (Ammunition)

Antiaircraft Gun

For Army Land Defense

Mode1-88, 70 mm antiaircraft gun (Includes those for mounting on airplanes.

1160 (210,000 rounds)

Model-4, 70mm antiaircraft gun

200 (190,000 rounds)

80mm antiaircraft gun

240 (360,000 rounds)

120mm antiaircraft gun

95 (50,000 rounds)

150mm antiaircraft gun

5 (3,000 rounds)

For Nary Land Defense and for Vessels

Mode1-1, 127mm antiaircraft gun

30

500 rounds per gun

127mm antiaircraft gun

100

500 rounds per gun

120mm antiaircraft gun

410

400 rounds per gun

Mode1-98, 100mm antiaircraft gun

50

500 rounds per gun

Total

1,350

Chart 5-b

Antiaircraft Equipment to be Produced in the First Half of 1945 Fiscal Year

(Cont'd)

Classification

Quantity ([Estimated])

Antiaircraft Machine Gun

25mm antiaircraft machine gun

7,200

3,500 rounds per gun

20mm antiaircraft machine gun

(Type-4 twin mount)

900 (30,000,000)

13am antiaircraft machine gun

1,00

4,000 rounds per gun

40mm antiaircraft machine gun

560

4,000 rounds per gun

Searchlight

1.5 m reflector

230

2 m reflector

106

Antiaircraft Balloon

Type 1

10

Type 2

175

Small Sound Locator

110

80mm Barrage Mortar Shell

(300,000 rounds)

Antiaircraft Kits

1,600

Notes:

Employment of antiaircraft firearms for land defense shall be coordinated between the Army and the Navy.

Chart 6

Antisubmarine Weapons to be Constructed in the First Half of Fiscal Year 1945

Classification

Quantity

Distribution

Responsibility for Procurement

Sonar Equipment

2,000

Navy

4

Navy

Antisubmarine Radar

1,200

Army

200

Navy

1,000

Magnetic Radar for Aircraft

1,500

Army

300

Navy

1,200

Mine

Ordinary

30,000

Navy

For Beaches

20,000

Navy

Depth Charge

50,000

Army

10,000

Army

10,000

Navy

40,000

Nary

40,000

Chart 7

Fuel and Powder to be Produced in Japan, Manchuria and China

Classification

Quantity

Remarks

For Fiscal Year 1945

For the First Half of Fiscal Year 1945

Liquid Fuel

Aviation gasoline

60,000 kl

26,000 kl

Ordinary gasoline

50,000 kl

23,000 kl

Alcohol

400,000 kl

120,000 kl

Methanol

50,000 kl

20,000 kl

Heavy oil

Heavy oil for Navy use

250,000 kl

120,000 kl

Heavy oil for civilian use

160,000 kl

60,000 kl

Kerosene

130,000 kl

50,000 kl

"RO" - Go Fuel

40,000 tons

10,000 tons

Powder (Explosive)

Powder

70,000 tons

Army 10,000 ton

Navy 25,000 ton

Details of the allotment of powder and explosive to be used in the first half of fiscal year 1945 shall depend upon the distribution of weapons.

Explosive charges

80,000 tons

Army 20,000 tons

Navy 20,000 tons

Notes:

1. The distribution is determined separately.

2. Measures shall be jointly taken by the Army and the Navy to drastically increase the production of turpentine extracted from pine roots and other oils which are not mentioned in this table.

Appendix III

Naval General Staff Secret Document No 31

Data: 6 April 1945

Subject: Conference on War Preparations in the First Half of Fiscal Year 1945

From: Vice Chief of the Naval General Staff

To: Vice Minister of the Navy

In order to cope with the recent critical situation, it is requested, that arrangements be made to carry out immediately and resolutely the plans appended hereto concerning this subject matter. Relative to the conference, it is requested that the details be worked out by competent persons.

An agreement on the war preparations to be made during the first half of fiscal year 1945 was made between the Naval General Staff and Army General Staff Headquarters, as described in the annex.

Distribution:

Chief of Naval Aeronautical Department.

Chief Of Naval Technical Department.

Chief of Naval Civil Engineering Department.

Annex

I. Plan for War Preparations

A. In the first half-year period, efforts will be made to build

defense positions around Japan from which the advancing enemy can be destroyed, thus ensuring ultimate victory. The latter half of the year will be devoted to strengthening these fortifications in order that the offensive can be resumed at the earliest possible opportunity. These war preparations will be carried out as follows:

1. All war preparations will be carried out in the spirit of suicide attacks, and the total national power will be united into a fighting force that can furnish the necessary manpower for the coordinated war plans of the Army and Navy.

2. The main combat strength will be composed of air forces (including air special attack forces) and underwater and surface special attack forces. The greatest emphasis will be placed on the maximum development of their combat capabilities.

Relative to war preparations, other than those mentioned above, if they will not obstruct the build-up of the air forces and the special underwater and surface attack forces, priority will be given to important land defense forces, submarine forces, surface escort forces and supply forces in that order so that these forces, combined with the main forces, may meet the operational demands. In order to increase the air forces and the special underwater and surface attack forces to the size urgently required for these operations, it is expected that all other war preparations scheduled for completion prior to September will be postponed and those scheduled for completion after October will be temporarily suspended. Preparations for chemical warfare for both offen-

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sive and defensive operations will be effected promptly.

3. Relative to war preparations for intercepting the enemy at the center of our fortified region, all human and material strength will be mobilized so that they can be immediately and most effectively employed in action at the right moment. All possible steps will be taken to enable important combat forces to continue fighting with tenacity.

4. War preparations for the counteroffensive will be drawn up in a separate document.

B. Division of War Preparations

1. The first quarter of 1945 (from the beginning of April to the end of June):

a. The greatest emphasis will be placed on gaining control of the air and sea covering the area in which decisive action is being contemplated and especially on the destruction of enemy carrier task and occupation forces.

For this purpose emergency measures will be taken for the rapid build-up and employment of land-based air forces and special attack forces.

Preparations for offensive and defensive operations in the Homeland will be effected according to and in parallel with the foregoing program.

Specially designated surface forces will be ready by the end of June to conduct raiding operations on the sea near the Homeland. Steps will be taken to intensify the defense of industrial centers and commu-

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nications facilities against air attacks. Preparations for land combat on the Homeland will be carried out to the extent required by the war situation, provided that they do not obstruct other important war preparations of the Navy itself.

b. The protection to be given to surface traffic between Japan and Manchuria and China will be governed by the war preparations mentioned in the foregoing paragraph. Communications with the southern areas will be especially arranged so that they will be maintained even under the most serious combat situation. Sea transportation along the coasts of the Homeland will be so planned that it will be protected by land bases along the coast.

The surface-protecting forces will, for the time being, protect surface traffic between Japan and Manchuria and North China. Merchant vessels will be equipped with weapons which are adequate for antiaircraft and antisubmarine defense.

c. Most of the war materiel will be transported on suitable merchant vessels and the amount of supply will be kept to the minimum.

d. Preparations to frustrate the enemy's attempts to sever our short distance supply lines will be strengthened.

2. War preparations in the second quarter (from the beginning of July to the end of September):

a. An invincible structure will be established.

b. A portion of the preparations for counteroffensives will be carried out.

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c. Other war preparations will be the same as those prescribed for the first quarter.

d. Whether efforts are to be directed at preparations for war in the Homeland or at preparations for counteroffensives and sustained warfare will be decided according to the war situation in May.

3. War preparations in the third quarter (from the beginning of October to the end of December) and the fourth quarter (from the beginning of January to the end of March 1946):

War preparations prescribed for the second quarter will be continued and other programs for this period will be mapped out separately.

C. Urgent measures will be taken to procure important materials, especially for fuel and powder, so that a sufficient quantity can be rapidly supplied in Japan, Manchuria and China. The greatest emphasis will be placed on the securing of aircraft gasoline.

D. The Homeland will be organized so that production, training and war preparations can be carried out with the least possible amount of difficulty; the Homeland will be organized immediately into the front line with each area establishing a self-sustaining and self-defensive structure.

E. The overseas key areas will strive to establish self-sustaining and self-defensive structures.

II. Outline for the Execution of War Preparations

A. Aircraft with its Equipment and Facilities

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efforts will be made to elevate the actual working efficiency of factory workers and to secure and expand aircraft production, while taking every possible measure to minimize damage from air raids. At the same time, the combat strength required as the main force of the Navy will be built up according to the following plant

a. Maximum emphasis in air preparations will be directed toward annihilation of enemy carrier task forces. A capable force will be maintained and strengthened as quickly as possible during the first quarter of preparations and thereafter the strength necessary for destroying other enemy objectives will be reorganized. For this purpose, importance will be attached to the preparation of fighter, reconnaissance and attack planes. In order to increase the effectiveness of the attack planes, principal emphasis will be placed on the over-all conversion of attack planes into special attack planes, the combined use of special attack planes and special type planes with acceleration of the production of large, extremely powerful aircraft.

b. Relative to aircraft for antiaircraft defense, fighting power will be increased by improving the performance of the aircraft now in use, by converting them into special attack planes and by accelerating production of special type planes. Relative to aircraft to be employed in attacking enemy invasion forces, plans will be drawn up to convert most of the aircraft used in training and those presently in storage into Special attack planes by late April. At the same time, efforts will be made to accelerate production of small special attack

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planes and conversion of other aircraft into small, special attack planes as soon as possible. With reference to escort aircraft for sea communications, these will be replenished with second-line planes, in addition to the planes being used exclusively for this purpose. Relative to aircraft for attacking enemy air bases, they will be maintained and strengthened as long as such aircraft are available.

2. The number of aircraft to be produced: Standard aircraft will be maintained and strengthened according te Chart 1. Special planes will be maintained and strengthened in accordance with the following section on Special Attack Planes.

3. Equipment and facilities relative to aircraft:

a. Antiaircraft defense measures for aircraft production facilities (including important related production facilities) will be completed quickly and thereafter intensified. Underground aircraft production facilities, capable of producing 1,200 frontline planes monthly (including special planes), will be completed during the first quarter of preparations.

b. Air bases will be prepared and strengthened in the following general order: Kyushu Area bases to be used for the coming decisive battle, Kanto Area bases for launching attacks on enemy carrier task forces, bases for use by special attack planes of the training air group and rear echelon bases in the Sanin, Korea and Hokkaido areas.

c. In addition to strengthening the radar network for air operations (including air defense), and the air defense for communica-

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Chart 1-a

Production of Aircraft for the First Half of Fiscal Year 1945

Naval Aircraft

Type of Aircraft

Minimum Requirement (The majority will be produced at dispersed underground factories The minimum requirements must be met at all costs)

Ultimate Goal

Remarks

Fighters

Shiden, Improved Model

2,400

2,400

Zero Fighter

1,800

2,700

To be converted into Shiden, Improved Model, as soon as possible

Raiden, Improved Model

600

Saiun

300

300

Ginga

100

100

Total

4,600

6,100

Recon Plane

Saiun

850

850

Bomber and Attack Planes

Ginga

700

700

Ryusei

300

300

Renzan

56

100

Total

1,050

1,100

Chart 1-b

Production of aircraft for the First Half of Fiscal Year 1945

(Cont'd)

Naval aircraft

Type of Aircraft

Minimum Requirement (The majority will be produced at dispersed underground factories. The minimum requirements must be met at all costs)

Ultimate Goal

Remarks

Patrol Planes

Type 1 Land Attack Planes

240

250

Scheduled to be employed as attack planes

Tokai

250

Total

240

500

Recon Seaplanes

Seiran

80

Transport Planes

Type Zero and Type I Transport Planes

320

Training Planes

Medium Land-based Training Planes

200

Utility Trainer

200

Type Zero Training Fighters

350

Type 99 Training Bombers

100

Training Planes Tokai

200

Total

1,050

Grand Total

6,740

10,000

ions, supply and repair facilities, everything will be done to improve these defense facilities in order to minimize damage from air attacks and maintain secrecy of preparations.

d. Weapons for air operations will be readied in sufficient quantity to maintain the air potential.

e. Additional details will be discussed in other sections, 4. Readying a carrier-based air force: Some of the already completed aircraft carriers are slated to be manned by special attack forces in the middle of 1945 and details will be discussed elsewhere.

B. Special Attack Craft and Related Facilities

1. Special attack craft will be readied in accordance with Chart 2. Special emphasis will be placed on the special underwater attack force, which will be the main strength in the annihilation of the enemy's invasion force and in the interception of his short-range supply lines. Also it will be the training force to be used against the enemy carrier task force. If necessary, details for preparations will be discussed elsewhere.

2. Related Facilities.

a. Production facilities will be dispersed and moved underground as promptly as possible and production will be greatly increased.

b. Various base facilities will be completed within the first quarter and strengthened thereafter. Additional details will be discussed separately.

C. Ships

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Chart 2-a

Special Attack Craft

Period

First Quarter From April to June 1945

Second Quarter

From July to September 1945

Third Quarter

From Oct 1945 to End of Mar 1946

Remarks

Classification

Special-type Aircraft

2,000

To be determined by a later conference

To be replenished with Suisei, Tenzan, Ki-115 and others. The details will be determined by a special conference.

Oka Plane

900

900

"

A special conference will be held to discuss improvement of performance

Kikka Plane

300

"

Shusui Plane

450

750

"

To be constructed through cooperation between the Army and Navy. Approximately one-third of this number will be constructed by the Navy.

Karyu Plane

5

"

Kaiten Human Torpedo

300

360

300

Chart 2-b

Special Attack Craft

(Cont'd)

Period

First Quarter

From April to June 1945

Second Quarter

From July to September 1945

Third Quarter

From Oct 1945 to end of March 1946

Remarks

Classification

Kairyu Midget Submarines

350

550

1,000

To be constructed by advancing the deadline as much as possible. Improvement in the performance of the Kairyu will be considered in the last half of the fiscal year

Koryu Midget Submarines

110

430

1,000

Small Submarines

40

120

Of the submarines scheduled for the first half, 40 will be readied by August. They will be equipped to recharge while cruising underwater as soon as possible

Shinyou

No. of Vessels

1,680

1,800

1,200

Engines

2,250

2,250

1,300

Notes

The number scheduled for the Third Quarter and thereafter is an approximate figure.

The details shall be determined by a later conference.

1. Ships will be readied in accordance with Chart 3. All ships will be made as compact as possible and whenever possible small ships will be used.

2. Armament

a. Armament will be conducted strictly in accordance with the priority system. At the same time, ships capable of carrying special attack planes will, if possible, be fitted for this purpose.

b. Every effort will be made to simplify the fitting out of vessels. At the same time, coast defense ships, starting with those to be newly constructed, will be equipped, if at all possible, with a mixed firing boiler in order to shorten the construction time. Above all, the construction period for antisubmarine craft and submarines will be drastically reduced and the submarines will be fitted so that they may recharge their batteries while cruising underwater.

c. Details will be discussed elsewhere.

3. Air defense measures will be taken to protect the construction of ships as well as ships already constructed.

D. Weapons (Excluding weapons employed in aerial combat). Weapons will be readied in accordance with Chart 4.

E. Surface Defense

Defense of communications between Japan, Manchuria and China

and, especially, defense of the seas adjacent to the Homeland, the Tsushima Straits, the Japan Sea and North China, will be stressed. Harbor and bay facilities, air bases, communications facilities, defense

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Chart 3-a

Ship Construction

Priority

Type of Ships

Requirement

Notes

4

Aircraft Carriers

2

Work will be suspended temporarily after the launching. Their use will be determined separately. Work on the "Ibuki" and "Kasagi" sill be suspended temporarily.

4

Otsu

1

Work will be suspended temporarily.

2

Destroyers

Tei

20

Six will be completely equipped in the first quarter of the fiscal year. Construction of the others will be started according to the situation. Loading of Kaiten will be made possible.

3

Submarines

Tei

2

Tei 2 (Bo)

5

In unavoidable cases torpedo-tubes will be equipped later.

2

High speed

16

2

Special type

2

Construction of ship No 5236 will be abandoned.

2

Supply

1

1

Escort-ships

Ko

30

Twenty will be completely equipped in the first half of the fiscal year. Construction of the others will be started according to the situation.

Hei

Tei

Chart 3-b

Ship Construction

(Cont'd)

Priority

Type of Ships

Requirement

Motes

3

Transports

First-class

5

Second-class

10

Small Patrol Boats

40

To be completed by July.

1

Ko

40

Auxiliary Escorts

Otsu

80

2

Light Minelayers

2

2

Converted Minelayers

6

To be completed by the end of June. (Four of them will be reconverted merchant ships.)

5

Special Landing Barges

460

200 will be made of iron and 200 of wood. 30 will be for amphibious purposes.

Remarks: If obstacles arise in the construction and equipping of the special attack craft, the date of completion for those expected to be completed by September will be extended, while those expected to be finished after September will be temporarily suspended.

Chart 4-a

Weapons

1. Antiaircraft Weapons

Classification of Weapons

Quantity

No. of Shells per gun or Projector

Remarks

AA Gun

Type-1 127mm gun

30

500

Armour piercing shells will be about 10% of land based AA Guns' shell.

127mm gun

100

500

120mm gun

470

400

Type 98 100 mm gun

50

500

Total

650

Large Calibre Machine Gun

40mm machine gun

500

4,000

1. Land based machine guns will be of vehicle types.

2. Armour piercing shells will be about 20% of all machine gun shells.

25mm machine gun

10,000

3,500

Including 2880 guns scheduled for delivery to the Army

13mm machine gun

1,200

4,000

Balloon, Kite

AA balloon

150

AA kite

1,600

Searchlight

150

Chart 4-b

Weapons

2. Land Combat Weapons

Classification of Weapons

Quantity

No. of Shells Per Gun or Projector

Remarks

Rocket Gun

200mm rocket gun

1,200

50

120mm rocket gun

4,000

50

ROTA gun

17,500

4

Bomb Launcher

For 250 kilo bomb

10,000

For 60 kilo bomb

20,000

Quick Firing Gun

Medium and Small calibre gun

200

300

Guns will be converted from shipboard guns

Large calibre gun

12

300

200mm short barrel gun

50

60

120mm short barrel gun

850

400

80mm gun

50

400

Others

80mm mortar

10,000

300

7.7mm machine gun

2,000

4,000

Rifle

100,000

300

Pistol

12,000

60

Grenade thrower

2,500

100

Small mine

150,000

Chart 4-c

Weapons

Classification of Weapons

Quantity

No. of Shells Per Gun or Projector

Remarks

Others

Attack mine

100,000

Stick mine i

150,000

Hand grenade (corn-shape)

100,000

Hand grenade

5,000,000

Molotov cocktail bomb

150,000

Incendiary grenade

60,000

Dynamite

100,000

Smoke bomb

60,000

Small smoke bomb

150,000

Steel helmet

1,000,000

Sword

300,000

Others

Secondary small arms necessary for the above mentioned weapons will be prepared.

Simple hand weapons will be decided later

Chemical Weapons

Gas mask

1,000,000

Light anti-gas suit

300,000

Anti gas cover

300,000

Neutralizer

Powder No 3

600 tons

Powder No 4

2,500 sets

Powder No 5

2,500 sets

Others

Secondary small arms necessary for the above mentioned weapons will be prepared. Preparation for positive chemical warfare will be decided separately

Chart 4-d

Weapons

Classification of Weapons

Quantity

No. of Shells Per Gun or Projector

Remarks

Smoke

Screen

Weapons

Smoke powder

3,000 tons

40 kilogram smoke screen apparatus

3,000 sets

Gunpowder

25,000 tons

Explosive

20,000 tons

Vehicles

Amphibious tank

70

Tractor

70

Other vehicles

To be decided later

3. Anti-submarine Apparatus [Split table here.]

Classification

Quantity

Remark

Depth Charge

40,000

Mine

30,000

Hydrophone, Magnetic Detection Apparatus

Necessary amount for the anti-submarine vessels and airplanes

4. Other Weapons

Necessary amount for vessels, planes and other strength will be prepared.

facilities, patrol facilities and repair facilities, which are necessary for antisubmarine and antiaircraft defense, will be readied and strengthened.

As for the defense of the Southern Area communications routes, every effort will be made to preserve and strengthen the coastal shipping lanes along the continent.

F. Defense of the Areas.

1. The defense priority for the various areas will be as follows:

a. Homeland, Ryukyu Islands, Bonin Islands and South Korea.

b. Central and North China, and North Korea.

c. Other areas.

2. Outline of Defense:

a. The Homeland, South Korea Area, Ryukyu and Bonin Islands sector:

(1) Defense of the Homeland area will be carried out under the plan that the Kanto, Kyushu, South Korean and Hokkaido areas will be major fortresses linked with each other by intermediate fortifications and that control will be maintained over the Tsushima, Tsugaru, and Soya Straits and the southwestern channels of the Homeland. As for defense of the Ryukyu and Bonin Islands, the existing program will be strengthened in order to covert them into truly impregnable strongholds.

Above all, special efforts will be directed toward completion of the facilities necessary for displaying the combat effi-

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ciency of the air forces and the special attack forces, which are to be used in the decisive battle, and toward perfection of communications facilities of every kind.

These defenses will be completed generally by the end of the first quarter and quickly strengthened during and after the second quarter.

(2) More thorough measures will be taken to strengthen antiaircraft defenses. These measures, which have already been discussed will be speedily completed so that the vital sources of the nation's fighting power, as well as vital supply stockpiles, may be developed to the maximum and so that various production capacities may be maintained at peak level on a long range basis.

(3) A strong and effective supply line, combining sea, land, and air routes, will be established.

b. Central China, North China, and Korea: Relative to defenses in Central China, North China and Korea, emphasis will be placed on disruption of enemy operations aimed at cutting off our Homeland from the continent. This operation generally will be conducted in accordance with the foregoing paragraph.

c. Other areas: Local defense facilities will be used and every effort will be made to strengthen these defenses.

G. Fuel and Powder "RO"

1. Fuel: The production goal for the principal fuels shall be as shown in the following table:

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First Quarter

Second Quarter

Homeland

Southern Area

Total

Homeland

Southern Area

Total

Aviation Fuel (kiloliters)

130,000

60,000

190,000

140,000

70,000

210,000

Heavy Oil (tons)

120,000

160,000

280,000

130,000

150,000

280,000

Ordinary Gasoline (kiloliters)

9,000

10,000

27,000

9,000

10,000

46,000

Light Oil (kiloliters)

8,000

27,000

2. Powder "RO" Ten thousand tons. This amount represents the total Army and Navy requirements.

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