Japanese Monograph No. 88

ALEUTIAN NAVAL OPERATION

MARCH 1942 - FEBRUARY 1943

PREPARED BY

MILITARY HISTORY SECTION

HEADQUARTERS, ARMY FORCES FAR EAST

DISTRIBUTED BY

OFFICE OF THE CHIEF OF MILITARY HISTORY

DEPARTMENT OF THE ARMY

FOREWORD

This monograph was drafted by Commander Jakuo Mikami, former Staff Officer in Charge of Operations, Navy General Staff. This record is based on official documents, personal papers, and the recollections of the writer and other former officers participating in this operation.

Other monographs covering the operations of the Japanese armed forces in the Aleutian Area are as follows:

Title

Period

Mono No

Aleutians Operations Record (Army)

May 42 - Aug 43

46

Northern Area Naval Operations

Feb 43 - Aug 45

89

--iii--

Preface

Through Instructions No. 126 to the Japanese Government, 12 October 1945, subject: 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 Demobilization 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 Demobilization 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, G2, Headquarters, Far East Command.

--v--

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.

--vi--

TABLE OF CONTENTS

Page No

Chapter I

Outlook

1

Chapter II

Background Information

4

Chapter III

Preparatory Steps for Aleutian Campaign

6

Preparation by Imperial General Headquarters

6

Combined Fleet Operational Preparations

10

Preparation by the Northern Naval Force

16

Intelligence Summary

29

Chapter IV

Summary of Preparatory Operations

32

Chapter V

Operations, Movements and Occupation

39

Development (General)

39

Details of the Second Mobile Force

43

Details of Adak-Attu Invasion Force

48

Details of the Kiska Invasion Force.

56

Details of the Main Body

64

Chapter VI

Summary of the Operations

71

Synopsis of Aleutian Invasion Force Movements (May - June 1942)

71

Chapter VII

Transport and Escort Operations

73

Chapter VIII

Withdrawal Operations

79

Causes Leading up to Withdrawal

79

Sea Battle off Komandorskie

80

Defeat and Withdrawal from the Aleutians

82

--vii--

MAPS and CHARTS

Map No 1

Aleutian Invasion Force Movements, June 1942

35

Chart No 1

Combined Fleet Operational Preparations

12

Chart No 2

The First Distribution, Northern Naval Forces

18

Chart No 3

The Second Distribution, Northern Naval Forces

23

Chart No 4

The Third Distribution, Northern Naval Forces

24

Chart No 5

Distribution of All Forces

26

Chart No 6

2d Mobile Force

44

Chart No 7

Adak-Attu Invasion Force

50

Chart No 8

Kiska Invasion Force

57

Chart No 9

Kiska Defense Force

61

Chart No 10

Northern Naval Force, 10 July 1942

67

Chart No 11

Schedule for Transportation to West Aleutian Islands, 1 Nov 42 - 11 Feb 43

77

--viii--

CHAPTER I

Outlook

In the First Phase of the Pacific War Operations, the Imperial Army and Navy were successful in destroying important bases in the Orient which belonged to the United States, Great Britain and the Netherlands. Following this, Japan engaged in enlarging and securing the strategic positions won in the southern area.

During March and April of 1942, the Navy had achieved success in the Indian Ocean in addition to carrying out active submarine operations along the eastern coast of Africa and in South Australian waters. The Navy also held the offensive in northern New Guinea and the Solomon Archipelago areas. This created a critical menace to enemy lines of communication between the United States and Australia.

Further, the Army was making good progress in the execution of its operations in Burma after the conquest of the Philippines.

On 18. April 1942, an enemy task force approached the Homeland. It had broken through the patrol boat line which extended north and south some seven hundred miles east of Tokyo. Early in the afternoon of the same day, about fifteen enemy planes carried out an indiscriminate bombing of Tokyo and other points. An increasing number of enemy submarines was also encountered in the vicinity of the patrol boat line of defense.

Considerable losses had been suffered by the fleets of the United States and Great Britain up to the time of the Battle of the Coral Sea

which was fought on the 7th and 8th of May 1942. The remainder of their fleet, which was still of considerable strength, was endeavoring to regroup and reestablish its naval and air strength. These activities were centered around their main base of Hawaii. Efforts were also underway by the enemy to strengthen defense of its linos of communications between the United States and Australia.

As part of its tactics, the enemy showed some indications of employing "hit and run" methods, operating from Midway and Aleutian Archipelago areas.

At the beginning of 1942, the nearest territory of the United States to the northern Kurile Islands was the Aleutians. They are located within bombing distance of the Kuriles. These islands, together with Midway, represented two extremely important points in the northern Pacific. This was considered the only available invasion route from the north to the Homeland which could be used by enemy task forces.

About the beginning of March 1942, the Imperial Navy and Array were making plans for the Second Phase of our Greater East Asia Operations. The objective was to bring about a speedy end of the conflict by keeping the United States and Great Britain on the defensive all of the time. The Navy insisted on conducting offensive operations against important areas outside the zone which had been occupied already. During the planning discussions, Midway, the Aleutians, Fiji, Samoa and New Caledonia were studied as the main targets to be invaded

--2--

during this phase of operations.

Japan's move into the Aleutians was conceived as a flanking movement to protect the forces at Midway from a possible attack from the north. This monograph pertains only to the Operations in the western Aleutians.

Provided Japanese forces could occupy the western Aleutians, the bases for future aerial operations could be advanced closer to vulnerable targets. At the same time the air patrol to the east of the Homeland, combined with the surface patrol of the Eastern Pacific Screening Force, would provide a perfect shielding opportunity for Japan ... Thus, enemy task forces could be completely checked. Potential invasion from the north, and communication links between the United States and Russia would then be obstructed.

--3--

CHAPTER II

Background Information

There was no reliable intelligence Information available which pertained to the enemy's situation in the Aleutians. Consolidation of various equivocal reports, however, revealed that there were fairly extensive military installations at Dutch Harbor, and that some installations existed on Adak, Kiska and Attu. It was also reported that there were present several destroyers, two gun boats and a carrier for small-type flying boats.

Dutch Harbor, Adak, Kiska and Attu were considered as the most important areas in the Aleutian Archipelago. These strategic points were, selected as the invasion targets. Adak and Attu Islands are both about 30 miles long and 12.3 miles wide. Kiska is a small island about 22 miles in length and 6.7 miles in width. The islands are mountainous almost to the shore line with very little level land area anywhere. The soil is sterile and there are few trees. The highlands of these islands are generally rocky and steep, making the establishment of fortifications and airfields very difficult. They are bound by the frigid Bering Sea in the north and the more temperate Japanese currents in the North Pacific Ocean. It is in this zone where weather is bora, characterized by violent gales, heavy precipitation, long periods of fog, and rapid-unpredictable changes of temperature. All in all, these combinations make the islands a very desolate spot.

--4--

Dutch Harbor, located on Unalaska Island, is a port which will easily accommodate a large force. It is operable the year around. It was presently being used by the enemy as a submarine and seaplane base. More than twenty enemy planes were estimated to be operating from Dutch Harbor and Kodiak. Other than several seaplane tenders and small-type ships, there was nothing to indicate a large force being present at Dutch Harbor. The garrison force for land defense had been reinforced recently, and it was confirmed that four garrison units were stationed there under the command of a major general. The majority of the strength was estimated to be in the vicinity of Dutch Harbor.

The Bay of Alliance on Adak Island could harbor a large fleet. In addition, a wireless station had been established on the island.

It had been reported, but not confirmed, that wireless and observatory stations were operating on Kiska, and between two to three hundred marines were believed to be stationed there. There is excellent anchorage suitable for basing flying boats. The distance from Kiska to Shimushu Island on the northern tip of the Kuriles is about seven hundred miles.

It was also believed that there was a wireless station, observatory and a garrison unit of unknown strength on Attu. The anchorage is also usable for seaplanes. The distance from Attu to Shimushu is about six hundred miles.

--5--

CHAPTER III

Preparatory Steps for Aleutian Campaign Preparation by Imperial General Headquarters

As has been mentioned in the Outlook (Chapter One), the initial operations of the overall campaign had been successful. The Homeland was thought relatively safe from any enemy attacks other than from submarines. On the eastern front, the Imperial forces had captured Wake Island, strengthened positions in the Marshall Islands area, and established a protective screen of patrol boats in an area about six to seven hundred miles east of the mainland as a precaution against any possible enemy task force attack moving toward Japan proper.

It was borne in the minds of the Imperial General Staff, however, that it was not altogether impossible for enemy heavy bombers to launch an attack against the Homeland, Hokkaido or the Kuriles, provided enemy planes were based on the western Aleutians. It was, therefore, necessary to formulate counter-measures to cope with this possibility. The Navy Section of Imperial General Headquarters had started to study the Second Phase Operations about the first part of February. Close liaison was maintained with the Commander-in-Chief of the Combined Fleet in making this study. At that time, no idea of the Midway-Aleutian Invasion was discussed, however. The Combined Fleet persistently advocated an invasion of Midway, but did not gain approval from the Chief of the Navy General Staff as he (Admiral Nagano)

--6--

insisted on the plan to occupy Fiji, Samoa and New Caledonia, even though Combined Fleet Top Secret Operational Order Number One, dated 5 November 1941, did mention Midway and the Aleutians as points to be invaded or destroyed at the earliest opportune moment.

About the time the Imperial Army conceived the plan for invasion of the Aleutians so as to cut United States and Soviet lines of communications, the Navy General Staff agreed to the proposed operation and that it would be carried out by part of the Fleet.

On 2 April 1942, Combined Fleet Headquarters submitted a draft of an operational plan to be followed by the Combined Fleet during the Second Phase of the operations. In this draft it was planned that the Aleutian Operations would be carried out at the start of the phase. Part of the Fleet was to be committed in this operation. Following this, the Midway Operation would be carried out in early June. Then the Fiji, Samoa and New Caledonia Invasions were to be executed. There were heated discussions regarding this proposal between the Navy Section of Imperial General Headquarters and the Combined Fleet. Finally, a compromise was reached through a revision of the plan to allow for conducting the Midway and Aleutian Invasions simultaneously in early June. This was agreed to by Admiral Nagano on 5 April 1942, A directive for the Second Phase Operations was issued by the General Headquarters on 16 April 1942 to that effect.

The Halsey-Doolittle Air Raid on 18 April 1942, referred to in Chapter One, was one of the reasons for fostering the operational

--7--

idea to invade Midway and the Aleutians at that time. As indicated by the directive mentioned in the preceding paragraph, this plan was conceived as part of the operational directive two days before the raid was launched on Tokyo. The raid did have a side effect, however, in that it was used as a forceful argument in not postponing the invasions. Every effort was made by the Imperial Navy during April and May to complete preparations as scheduled. However, the return of the Second and Third Fleets from the Indian Ocean area late in April, as well as the damage suffered by the two carriers Zuikaku and Shokaku in the Battle of the Coral Sea, combined to make it impossible to complete the necessary preparations by late May. It was recommended to the Commander-in-Chief of the Combined Fleet that the invasions be postponed due to incomplete preparations, but Admiral Isoroku Yamamoto (C in C Combined Fleet) insisted on executing the invasions as scheduled, and referred to a possible second threat of a "Halsey-Doolittle-type air raid" when he rendered his decision.

On 5 May, Imperial General Headquarters Navy Order Number 18 set in motion the operations to capture Midway and points of strategic value in the western Aleutians. Admiral Yamamoto was directed to execute this order in coordination with the Imperial Army. Navy Directive Number 94 was issued ordering that the operation be carried out according to the following Joint Central Agreement on the Aleutian Operations, dated 5 May 1942:

--8--

"Object of the Operation:

Object of this operation is to capture or demolish points of strategical value on western Aleutian Islands in order to check the enemy's air and ship maneuvers in this area.

"Operational Policy:

The Army and Navy, in close cooperation with each other, will invade Attu and Kiska Islands and will destroy enemy installations and equipment on Adak Island.

"Operational Outline:

1. The Army and Navy, in close cooperation with each other, will capture Adak Island and withdraw after having demolished enemy installations and equipment. Following capture of the island, the Army troops and Navy Special Landing Forces will capture Attu and Kiska Islands respectively. They shall hold these two islands until the coming winter. .

2. The Navy will provide strong support for the invasion force and at the same time employ a carrier unit to raid Dutch Harbor for the main purpose of reducing enemy air strength prior to our landing.

"Commanders and Strength:

1. Navy Commander will be the Commander-in-Chief of the Combined Fleet and the greater part of the Combined Fleet will be used.

2. Army Commander will be the Commander of the North Sea Detachment, Major Matsutoshi Hozumi. Strength will be composed, chiefly, of one infantry battalion and one engineer company.

"Start of Operations:

The Aleutian Operation and the Midway Operation will begin at about the same time in early or mid-June.

"Point of Assembly and Date:

Invasion Forces will assemble at Akkeshi Bay (Hokkaido) on or about 23 May 1942. The Navy will be responsible for the escort of Army units from point of embarkation to the assembly point.

"Chain of Command:

1. The Commander of the 5th Fleet will take operational command of Army units immediately after the time of assembly.

2. In case both Army and Navy units are engaged in the same area in land or landing operations, the senior commander will take charge of the operations.

"Land Defense of the Islands:

The land defense of Kiska and Attu Islands will be assigned

--9--

to the Navy and the Army respectively.

"Communications:

Communications will be maintained in accord with the Joint Central Agreement Between the Army and Navy for Aleutian, Midway and Fiji Islands Operational Communications.

"Transportation and Supply:

1. The Navy will offer one transport for the transportation of Army troops during the operational period.

2. The Navy will be responsible for supply of the Army and for evacuation of Army patients.

"Maps to be Used:

This will be the Military Grid Chart of the Northern Pacific.

"Time:

Tokyo Standard Time will be used.

"Name of Operation:

This operation will be called the Aleutian Operation."

In compliance with this directive, the Navy activated the Maizuru 3rd Special Naval Landing Force with 550 men, commanded by Lieutenant Commander Hifumi Makai, and a construction unit of 750 men. Both units were assigned to the 5th Fleet.

The Army activated the North Sea Detachment, composed chiefly of the 301st Independent Infantry Battalion, 301st Independent Engineer Company and a service unit. The Detachment of 1,143 men was commanded by Major Matsutoshi Hozumi. Following the assembly at Ominato on 23 May 1942, it was placed under the operational command of the 5th Fleet.

Combined Fleet Operational Preparations

The Midway Operation was to be conducted by the Main Strength of the Combined Fleet, while the conceived "flanking movement" into

--10--

the Alaskan waters would be carried out by a lesser unit.

As provided in the previously mentioned directives from the Navy Section of Imperial General Headquarters, the Commander-in-Chief of the Combined Fleet assigned the Aleutian Operation to the Northern Naval Force, Main Strength of which was the 5th Fleet.

Operational orders were issued on 12 May 1942. Units scheduled to participate in the Aleutian Operation were directed to assemble at Ominato in the Northern Homeland area and prepare for the operation.

For information regarding the Midway Operation, refer to Monograph Number 93 for the over-all operational policy of the Eastern Pacific Operations.

Combined Fleet Headquarters issued orders containing instructions for the Aleutian (AL) Operations which included deployment and missions for the Northern Naval Force as follows:

"This operation will be carried out in conjunction with the Midway Operation. To carry out these operations, the Main Strength of the Combined Fleet will be used. The Commander-in-Chief of the Combined Fleet will be the over-all commander.

"Invasion forces will assemble toward the end of May in the Bay of Akkeshi. Using Combined Strength of Army and Navy Landing Forces, Adak Island will be occupied on about 7 June. After having destroyed all military installations there, the occupation force will withdraw from the Island. Immediately thereafter the Naval Landing Force will invade Kiska while Army troops will capture Attu. The islands will be held until the coming winter. It is scheduled that a small base suitable for seaplanes and submarines be developed on Kiska."

The Combined Fleet Order provided for deployment of the Northern Naval Force according to the following plan (also see Chart No 1):

--11--

COMBINED FLEET OPERATIONAL PREPARATIONS

Chart No. 1

--12--

The Main Body of the Northern Naval Force, under the 5th Fleet Commander, Vice Admiral Boshiro Hosogaya, would operate in support of the entire Aleutian Operation. The strength of this body would consist essentially of the following ships:

Heavy Cruiser: Nachi

Destroyers: Nenohi and Hatsuharu from the 21st Destroyer Division

The 2nd Mobile Force would operate under the 4th Carrier Division Commander, Rear Admiral Kakuji Kakuta, with the mission of launching air raids on Dutch Harbor and other important points in addition to the annihilation of the enemy fleet. The strength of this force would consist, essentially, of the following ships:

Light Fleet Aircraft Carriers: Ryujo and Junyo from the 4th Carrier Division

Heavy Cruisers: Takao and Maya from the 2nd Section of the 4th Cruiser Division.1

Destroyers: Ushio, Oboro and Akebono from the 7th Destroyer Division.

Oiler: Teiyo Maru

The Adak-Attu Invasion Force would operate under the 1st Destroyer Squadron Commander, Rear Admiral Sentaro Omori: and have

1. Note: The Maroko and the Haguro from the 5th Cruiser Division were originally assigned to this force; however, the 5th Cruiser Division was late in returning from the Battle of the Coral Sea.

--13--

the mission of the Adak-Attu Invasions. The strength of this force would consist, essentially, of the following ships:

Light Cruiser: Abukuma

Destroyers: Wakaba and Hatsushimo from the 21st Destroyer Division

Transport: Kinugasa Maru

Converted Mine Layer: Magane Maru

The Kiska Invasion Force would operate under the commanding officer of the cruiser Kiso, Captain Takeji Ono; and have the mission of invading Kiska. Its strength would consist, essentially, of the following ships:

Light Cruisers: Kiso and Tama from the 21st Cruiser Division.

Destroyer: Hibiki, Ikazuchi and Inazuma from the 6th Destroyer Division

Converted Cruisers: Awata Maru and Asaka Maru from the 22nd Picket Boat Squadron

Destroyers: Hibiki, Ikazuchi and Inazuma from the 6th Destroyer Division, and the Hokaze

Transports: Hakuzan Maru and Kumakawa Maru

Converted Gun Boats: Kaiho Maru, Shunkotsu Maru and Hakuho Maru

Submarine Chasers: 3 from the 13th Subchaser Division

The Submarine Unit would be under the 1st Submarine Squadron Commander, Hear Admiral Shigeteru Yamazaki; and would be responsible

--14--

for patrolling, locating and attacking important enemy operational areas and ships. Its strength would consist, essentially, of 6 I-type submarines from the 1st Submarine Squadron.

The Seaplane Force would be under the command of the commanding officer of the Kimikawa Maru, Captain Keiichi Ujuku; and would cooperate in landing operations, locating enemy ships, and executing attacks. Its strength would consist, essentially, of the following ships:

Seaplane Tender: Kimikawa Maru (with 8 reconnaissance seaplanes on board)

Destroyer: Schiokaze

The Base Air Force would operate under the commanding officer of the Toko Air Group Detachment, Commander Sukemitsu Ito; and have the mission of locating and attacking enemy ships. The strength of this force would consist, essentially, of the following:

Transports: Kamitsu Maru, Second Hino Maru, Fifth Seiju Maru and Second Hishi Maru

Aircraft: 6 Flying Boats from the Toko Air Group

The Scouting Force would be under the commander of the 22nd Picket Boat Squadron, Vice Admiral Shigenori Horiuchi; and have the mission of scouting. Its strength would consist, essentially, of the 22nd Picket Boat Squadron.

The Ogasawara Force would consist of the 7th Base Force of the 5th Fleet, and operate under command of the 7th Base Force Commander,

--15--

Rear Admiral Seiichiro Fujimori. The assigned mission of this force was scouting.

In addition, the 24th and 27th Destroyer Divisions would support the operations if the situation demanded, along with the 2nd Battleship Division (Ise, Hyuga, Fuso and Yamashiro). However, they remained assigned, basically, to the Midway Operations.

Preparation by the Northern Naval Force

Northern Naval Force Order Number 24, issued on 20 May 1942 by the Commander of the 5th Fleet in preparation for the Aleutian Operation included the deployment of strength for use in this operation. According to the plan, this was aligned in Three Phases:

The First Distribution of forces was designed to cover the approach and initial invasion effort until the time when control had been gained by the land forces.

The Second Distribution was designed to support the operation during the period of consolidating and establishing the defense, and was to be in effect until there was little possibility of a counterattack by the enemy.

The Third Distribution set a limiting date for completion of all objectives, and established the planned reallocation of ships and duties to guard the northern area and approaches to the Japan Homeland. The effective date established was to be 20 June 1942.

The assignments given the various units and the ships which were planned as participants in the operation's Three-Phase Plan are

--16--

included in the following text.

1. The First Distribution

In the First Distribution and deployment of naval forces for the Aleutian Operation (see Chart No 2), the Main Body of the Northern Naval Force, consisted of the heavy cruiser Nachi, and the two destroyers Nenohi and Hatsuharu, was placed under the direct command of the Commander of the 5th Fleet (Vice Admiral Boshiro Hosogaya). The mission of the Main Body was that of supporting the entire Aleutian Operation.

The 2nd Mobile Force, consisting of the light fleet aircraft carriers Ryujo and Junyo, the two heavy cruisers Takao and Maya, and the three destroyers Ushio, Oboro and Akebono, and the oiler Teiyo Maru, under the command of the 4th Carrier Division Commander, would launch air raids on Dutch Harbor, Adak and Kiska, annihilating the enemy fleet during this first phase.

The Adak-Attu Invasion Force, consisting of the light cruiser Abukuma, and the two destroyers Wakaba and Hatsushimo, the transport Kinugasa Maru, and the converted mine-layer Magane Maru, placed under the command of the 1st Destroyer Squadron Commander, was charged with the responsibilities of destroying enemy military installations on Adak, and invading Attu. The Seaplane Force, consisting of the seaplane tender Kimikawa Maru, and the destroyer Shiokaze. was assigned to the Adak-Attu Invasion Force at this time. The Array North Sea Detachment would be transported by the transport Kinugasa Maru and the

--17--

Chart No. 2

--18--

destroyer Shiokaze.

The Kiska Invasion Force, consisting of the two light cruisers Kiso and Tama, the two converted cruisers Awate Maru and Asaka Maru, the four destroyers Hibiki, Ikazuchi, Inazuma and Hokaze, the two transports Hakuzan Maru and Kumakawa Maru, the three converted gun boats Kaiho Maru, Shinkotsu Maru and Hakuho Maru, would invade Kiska during this first phase. It is noted that the destroyer Hokaze was added to the invasion force at this time. The Hakuzan Maru and the Kumakawa Maru were to transport the Maizuru 3rd Special Landing Force to Kiska.

In support of the operations during this phase, the following additional forces were also designated:

The Submarine Unit, under command of Rear Admiral Shigeteru Yamazaki, 1st Submarine Squadron Commander, would be responsible for necessary patrolling, locating and attacking vital operational areas, including sighted enemy vessels. The strength of tills unit would be six I-type submarines assigned from the 1st Submarine Squadron.

The Seaplane Force, commanded by Captain Keiichi Ujuku, commanding officer of the seaplane tender Kimikawa Maru. was charged with locating enemy ships and attacking them, as well as rendering necessary cooperation with the landing operations. The strength of this force would consist, essentially, of the seaplane tender Kimikawa Maru with eight reconnaissance seaplanes on board, and the destroyer

--19--

The Base Air Force, under Commander Sukemitsu Ito, commanding officer of the Toko Air Group detachment, had the assigned mission of locating and attacking enemy ships. The strength of the Base Air Force was to consist of six flying boats from the Toko Air Group, and the four transports Kamitsu Maru, the Second Hino Maru, the Fifth Seiju Maru and the Second Hishi Maru.

The mission of scouting the enemy was assigned to the Scouting Force, commanded by the commander of the 22nd Picket Boat Squadron, Vice Admiral Shigenori Horiuchi.

In addition to the 22nd Picket Boat Squadron, the Ogasawara Force, commanded by Rear Admiral Seiichiro Fujimori, was also assigned a similar mission. This scouting force consisted of the 7th Base Force of the 5th Fleet.

In the event the situation warranted additional support, the Commander of the Northern Naval Force was given the prerogative of employing the 24th and the 27th Destroyer Divisions, in addition to the four battleships Ise, Hyuga, Fuso and Yamashiro from, the 2nd Battleship Division. These units, however, remained organically assigned to the Midway Invasion Force.

The Second Distribution was to take effect when control had been gained by the land forces.

2. The Second Distribution

For the second phase of the operation, it was planned that the Adak-Attu Invasion Forces would be dissolved and the surface vessels

--20--

allocated to these forces during the first phase would be incorporated into the element designated as the Main Body for the second phase. The land combat forces for the invasions would be reorganized as defense forces and would be aided in their operations by some local defense vessels. It was also planned at this time that any necessary strength required to complete the second phase of the operations would be reinforced from the Midway Invasion Force (see Chart No 3).

The Main Body of the Northern Naval Force during this phase would consist of the heavy cruiser Nachi, the three light cruisers Kiso, Tama and Abukuma, and the seven destroyers Nenohi, Hatsuharu, Wakaba, Hatsushimo, Hibiki, Ikazuchi and Inazuma. The mission would remain the same as in the first phase, viz. support of the entire Aleutian Operation.

The 2nd Mobile Force in executing its assigned mission in this phase would consist of the three light fleet aircraft carriers Ryujo, Junyo and Zukho, the two heavy cruisers, Takao and Maya, and the seven destroyers Ushio, Oboro, Akebono, Arashi, Nowake, Hagikaze and Maikaze, It is noted that it was contemplated to reinforce the 2d Mobile Force with the Zuiho, Arashi, Nowake, Hagikaze and Maikaze (the latter four being the 4th Destroyer Division) from the Midway Invasion Force. The main effort of the entire force during this phase would be to annihilate the enemy fleet.

The Submarine unit during the second phase would consist of six I-type submarines from the 1st Submarine Squadron plus seven I-type

--21--

submarines from the 2d Submarine Squadron, or a total of thirteen. The submarines assigned to the 2d Submarine Squadron were under maintenance repair in Japan proper at the time this plan was formulated on 20 May 1942. The entire Submarine Unit would operate under the command of the 1st Submarine Squadron Commander with the assigned mission of locating and attacking enemy ships.

The Seaplane Force during this second phase would consist of the two seaplane tenders Kimikawa Maru and Kamikawa Maru, and the destroyer Shiokaze. The Kamikawa Maru was to be assigned from the Midway Invasion Force. Captain Tarohachi Shinoda was placed in command of this force with the assigned mission of reconnaissance.

The Base Air Force, under the command of the commander of the Toko Air Group Detachment, consisted of six flying boats, and the four transports Kozu Maru, Second Hino Maru, Second Hishi Maru and the Fifth Seiju Maru, had the responsibility of patrolling the invasion area.

The Kiska Defense Force, under command of the 13th Subchaser Division Commander, Captain Toshio Mitsuka, would operate in two sections during the second phase. The First Section, the Kiska Coast Defense Force, would consist of the three submarine chasers Numbers 25, 26 and 27 of the 13th Subchaser Division, and the three converted gun boats Kaiho Maru, Shunkotsu Maru and Hakuho Maru. This coast defense force was charged with maintaining sea defense around Kiska and necessary scouting between Kiska and Attu. The

--22--

--23--

THE THIRD DISTRIBUTION

Chart No. 4

--24--

Second Section, the Kiska Land Defense Force, would consist of the Maizuru 3d Naval Special Landing Force, and was charged with establishing and maintaining necessary land defenses for Kiska. Necessary materiel would be unloaded from the two transports Hakuzan Maru and Kumakawa Maru in the anchorage.

The Attu Defense Force during this phase would consist of the Army's North Sea Detachment, and the mission would be that of maintaining necessary land defenses on Attu.

3. The Third Distribution

It was anticipated that as of 20 June 1942, the Aleutian-Midway Offensive Operations would be completed, and the occupation established. At that time it was intended to reorganize the Fleet for purposes of long-term defense of the newly won areas, in addition to establishing the defense of the northern areas which were possible approaches to the Homeland. The third phase of the operation and distribution of forces was planned as a major realignment of units (see Chart No 4).

The Main Body was to be reduced in size for this last phase, consisting of the heavy cruiser Nachi and the three destroyers Hibiki. Ikazuchi and Inazuma. Its mission was to continue rendering support of the entire Aleutian Operation.

A powerful support force was to be organized for this phase, and was to consist of two groups both under command of the 3rd Battleship Division Commander, Vice Admiral Gunichi Mikawa. The First Sup-

--25--

Distribution of All Forces

1st Distribution

2d Distribution

3d Distribution

Main Body

Main Body

Main Body

Nachi (CA)

Nachi (CA)

Nachi (GA)

Nenohi (DD)

Abukuma (CL)

Hibiki (DD)

Hatsuharu (DD)

Kiso (CL)

Inazuma (DD)

Tama (CL)

Ikazuchi (DD)

Nenohi (SD)

2d Mobile Force

Wakaba (DD)

1st Support Group

Ryujo (CVL)

Hatsuharu (DD)

Kongo (BB) - 4

Junyo (CVL)

Hatsushimo (SD)

Haruna (BB) - 4

Takao (CA)

Hibiki (DD)

Tone (CA) - 4

Maya (CA)

Inazuma (DD)

Chikuma (CA) - 4

Ushio (DD)

Ikazuchi (DD)

Akigumo (SD) - 4

Oboro (DD)

Yugumo (DD) - 4

Akebono (DD)

2d Mobile Force

Makigumo (DD) - 4

Taiyo Maru (AO)

Ryujo (CVL)

Kazagumo (DD) - 4

Junyo (CVL)

Kyokuto Maru (AO) - 4

Zuiho (CVO) - 1

Attu-Adak Force

Takao (CA)

2d Support Group

Abukuma (OL)

Maya (CA)

Hiei (BB) - 4

Wakaba (DD)

Ushio (DD)

Kirishima (BB) - 4

Hatsushimo (DD)

Oboro (DD)

Myoko (CA) - 5

Magane Maru (XCM)

Akebono (DD)

Haguro (CA) - 5

Kinugasa Maru (AP)

Arashi (DD) - 1

Kiso (GL)

Nowaki (DD) - 1

Tama (OL)

Hagikaze (DD) - 1

Abukuma (CL)

Kiska Force

Maikaze (DD) - 1

Nenohi (DD)

Kiso (CL)

Taiyo Maru (AO)

Wakaba (DD)

Tama (CL)

Hatsuharu (DD)

Awata Maru (XC)

Attu Defense Force

Hatsushimo (DD)

Asaka Maru (XC)

Kinugasa Maru (AP)

Genyo Maru (AO) - 6

Hibiki (DD)

Inazuma (DD)

Kiska Defense Force

2d Mobile Force

Ikasuchi (DD)

Coastal Defense Unit

1st Raiding Group

Hokaze (DD)

Kaiho Maru (XPG)

Ryujo (CVL)

Hakusan Maru (AP)

Shunkotsu Maru (XPG)

Junyo (CVL)

Kumasawa Maru (AP)

Hakuho Maru (XPG)

Takao (CA)

Kaiho Maru (XPG)

PCs Nos 25, 26, 27

Akebono (DD)

Shunkotsu Maru (XPG)

Land Defense Unit

Ushio (DD)

Hakuho Maru (XPG)

Hakuzan Maru (AP)

Oboro (DD)

PCs Nos 25, 26, 27

Kumagawa Maru (AP)

Urakaze (DD) - 4

Toho Maru (AP) - 4

Submarine Force

Submarine Force

2d Raiding Group

6 I-type SSs

6 I-type SSs

Zuikaku (CV) - 5

7 I-type SSs - 2

Zuiho (CVL)

Seaplane Tender Force

Maya (CA)

Kimikawa Maru (AV)

Seaplane Tender Force

Arashi (DD)

Shiokaze (DD)

Kimikawa Maru (AV)

Nowaki (DD)

Kimikawa Maru (AV) - 3

Hagikase (DD)

Scouting Force

Shiokaze (SD)

Maikaze (SD)

PTs

Hokaze (DD)

Fujisan Maru (AO) - 7

Chart No. 5

--26--

Ogasawara Force

Ogasawara Force

Attu Defense Force - 8

7th Base Force

7th Base Force

Magane Maru (XCM)

Kiska Defense Force - 8

Base Air Force

6 Flying Boats

Base Air Force

Submarine Force - 8

Kamitsu Mara (AP)

6 Flying Boats

#2 Hino Mara (AP)

Kamitsu Maru (AP)

Seaplane Tender Force - 8

#5 Seiju Maru (AP)

#2 Hino Maru (AP)

#2 Hishi Maru (AP)

#5 Seiju Maru (AP)

Ogasawara Force - 8

#2 Hishi Maru (AP)

Base Air Force - 8

Scouting Force

PYs

Scouting Force - 8

Awata Maru (XC)

Asaka Maru (XC)

Notes:

1 - To be part of reinforcement from Midway Invasion Force.

2 - under maintenance at time of planning.

3 - To be part of reinforcement from midway Invasion Force

4 - To be part of reinforcement from Southern Force.

5 - To be part of reinforcement from Submarine Force.

6 - There was no change contemplated.

7 - To be reinforcement from Submarine Force (6th Fleet).

8 - Same as for 2d Distribution.

Classification of Vessels:

AO

Oiler

CVL

Light Fleet Aircraft Carrier

AP

Transports

DD

Destroyer

AV

Seaplane Tender

PG

Gunboat

OA

Heavy cruiser

PC

Submarine Chaser

CM

Minelayer

SS

Submarine

GL

Light Cruiser

SC

Converted Cruiser

XC

Converted Cruiser

XPG

Converted Gunboat

Distribution:

lat Distribution was designed to cover the approach and invasion effort until the time when control bad bean gained by the land forces.

2nd Distribution was designed to support the operation during the period of consolidating and establishing defensive positions. and was to remain in effect until there was little possibility of a counterattack by the enemy.

3rd Distribution set a limiting date for completion of all objectives, sad established the planned reallocation of ships and duties to guard the northern area and approaches to the Japan Homeland (Effective date established was 20 June 1942.)

Chart No. 5 (contd)

--27--

port Group, under direct command of Admiral Mikawa, was to consist of the two battleships Kongo and Haruna, the two cruisers Tone and Chikuma, the four destroyers Akigumo, Yugumo, Makigumo and Kazagumo, and the oiler Kyokuto Maru. All of the vessels in this First Support Group were to be transferred from the Midway Invasion Force at this time. The Second Support Group, under command of the 5th Cruiser Division Commander, Vice Admiral Takeo Takagi, was to consist of the two heavy cruisers Myoko and Haguro, the battleships Kirishima and Hiei, the three light cruisers Kiso, Tama and Abukuma, the four destroyers Nenohi, Hatsuharu, Wakaba and Hatsushimo, and the oiler Genyo Maru. The Myoko and the Haguro were under repair in Japan at the time of the planning for this phase, but both heavy cruisers were expected to be ready for operation at the time of execution of this last phase. The four battleships were to be assigned from the Midway Invasion Force, and the oiler Genyo Maru from the Southern Force.

The Second Mobile Force, under command of the 4th Carrier Division Commander, Rear Admiral Kakuji Kakuta, would be reorganized into two raid groups for this third phase. The First Raiding Group, consisting of the two light fleet aircraft carriers Ryujo and Junyo, the heavy cruiser Takao, the four destroyers Ushio, Oboro, Akebono and Urakaze, and the oiler Toho Maru, would be under the direct command of Admiral Kakuta. The Urakaze and the Toho Maru were to be assigned from the Midway Invasion Force. The Second Raiding Group,

--28--

under command or the 5th Carrier Division Commander, Rear Admiral Chuichi Hara, was to consist of the fleet aircraft carrier Zuikaku, the light fleet aircraft carrier Zuiho, the heavy cruiser Maya, the four destroyers Arashi, Hagikaze, Nowake and Maikaze. and the oiler Fujisan Maru. The Zuikaku was under repair in Japan proper as a result of damages received in the Battle of the Coral Sea, but was expected to be ready in time of execution of this phase. The Fujisan Maru was to be assigned from the Submarine Force.

Other than the aforementioned revisions and regroupings, the assigned forces taking part in this Aleutian Invasion Operation remained the same as assigned in the Second Distribution.

Intelligence Summary

Available data on the military topography for the regions to be invaded was inadequate and out of date other than that they were rocky, peat-covered, fog-wrapped islets situated about 650 miles from Paramushio (Japan's important main supply base and defense bastion in the northern Kuriles). And that the western Aleutian Archipelago is situated between 50 and 53 degrees North Latitude, composed of volcanic islands each forming low and somewhat barren "tundra" zones.

About the middle of May 1942, secret seaplane reconnaissance was made of the areas west of Adak. Planes assigned to this mission were from the seaplane tender Kimikawa Maru, which was escorted by the light cruiser Kiso. Due to inclement weather, reconnaissance of

--29--

Adak was not too successful. Further, only telephotographic reconnaissance was possible for Kiska. An attempt to reconnoiter Attu was abandoned due to the bad weather.

Information regarding the enemy situation which had been gathered by reconnaissance prior to the Second Mobile Force's air raid on Dutch Harbor was also rather meager.

Prior to 26 May, the submarine I-9 had made air reconnaissance on the Attu, Kiska and Adak areas and reported that there was not a vessel, airplane or important installation at any of these places.

On 27 May, the submarine I-25 made a report as a result of its air reconnaissance of Kodiak, and listed one heavy cruiser (Astoria type) and one destroyer entering Kodiak. This report also stated that one destroyer and three patrol boats were sighted in Women's Bay, six miles southwest of Kodiak, and that two patrol boats were at Kodiak. This report indicated that there were no flying boats seen, and, with the exception of two barracks there were no air bases or hangars sighted in or near Women's Bay. Brilliant lights were observed near the mouth of the Busukire River which indicated that some work was being performed on some installations at three places three and one-half miles southwest of Kodiak.

On 29 May, the submarine I-19 reported that on a telescopic reconnaissance of Dutch Harbor two destroyers, one navy transport or mine-layer, and some patrol boats at the entrance were sighted. Further, according to reconnaissances, it was probable that two or

--30--

three destroyers were in the immediate area.

On 30 May, the submarine I-26 while on its way to the Seattle area reported sighting two war vessels seven hundred miles west northwest of Seattle. Both vessels, heading northwest, looked like heavy cruisers although one of them could have been a transport.

In addition, the Owada Communications Unit had been intercepting enemy radio communications continuously. The enemy codes and call signs were partially broken. Prior to 3 June 1942, through its use of direction finding equipment, the Owada Unit made an intelligence summary regarding ship movements: At Kodiak, it was stated that there were three or four ships, one of which was thought to be a light cruiser, while in the Dutch Harbor area three or four ships, including a powerful warship, were located. And at Sitka, it was reported that the intelligence information was similar to that reported by submarine reconnaissance.

Finally, the Paramushiro Air Base, located at the northern tip of the Kurile Islands, was completely equipped to allow land planes to advance operations to the western Aleutians in support of the invasions.

--31--

CHAPTER 17

Summary of Preparatory Operations

The foregoing Chapter Three included the plans as directed in the Northern Naval Force Order Number 24, dated 20 May 1942, for the deployment and distribution of strength. The ensuing chapter includes the instructions regarding the objectives, the tactics and schedule which were included in this operational order, as well as the changes that occurred since its inception up to the time of the execution of the Aleutian Invasion Operation.

With the purpose of the operation to: (1) Destroy the enemy forces and military installations at Dutch Harbor and Adak; (2) Attack and occupy Kiska and Attu so as to restrict and prevent enemy offensive sea and air operations in the North Pacific; and (3) To maintain our offensive policy, detailed plans and alternative plans had to be formulated.

Air raids on Dutch Harbor were planned after N-3 Day. (N-day is landing day) The carrier force was to destroy enemy forces and military installations in order to prevent the enemy from using Dutch Harbor as a base. Prior to N-1 Day, air raids were planned for Adak and Kiska destroying the enemy forces and military installations there.

On N-Day, the Special Naval Landing Force planned to attack and occupy Kiska. On the same day, the Army North Sea Detachment with reinforcements planned a surprise attack on Adak to destroy

--32--

military installations there. After accomplishing this mission on Adak, the Army North Sea Detachment was to advance on Attu and occupy the island.

The Submarine Force was to be deployed in the Seattle Area. The Seaplane Force was to be sent forward to the Kiska Area, while planes from seaplane tenders would reconnoiter the Bering Sea just north of the Aleutians subsequent to executing the landing operations on Adak.

The Northern Naval Force Operational Order Number 24 included five operational plans, each depending upon conditions at the time of the operations:

"Plan No. 1.

In case the situation developed as estimated and planned, operations would be conducted according to Operational Order Number 24.

"Plan No. 2.

In the event the United States Air Force was stronger than anticipated, and it became necessary to delay N-Day because of this situation, all units were to operate in a rendezvous area at points designated on the Chart of Aleutian Invasion Force Units (see Map No 1). when the enemy air force had been destroyed and N-Day reestablished, operational plans according to Operational Order Number 24 would be followed.

"Plan No. 3.

This plan was similar to Plan No. 2, above, with the exception that the proviso was based on U.S. task force strength delaying N-Day. The same instructions would be followed until N-Day was reestablished.

"Plan No. 4.

In case there was a powerful U.S. task force located in the area which required reinforcement of our forces, the invasion units would operate in the rendezvous area mentioned in Plan Nos. 2 and 3. The reinforcement would come from the Midway Invasion Force, as planned by the Combined Fleet Out-

--33--

line for the Aleutian Operations (see Chapter III). This force would consist of the 2nd Battleship Division, 9th Cruiser Division and the 20th, 24th, and 27th Destroyer Divisions under command of the First Fleet Commander, Vice Admiral Takasu. After this reinforcement had joined with the original unite assigned for the Aleutian Operation, and destroyed the enemy task force, N-Day would be reestablished and plans of Operational Order Number 24 would be followed.

"Plan No. 5.

In the event the landing at Adak was cancelled, the Adak-Attu Invasion Forces would suspend landing and destroying operations there and conduct only the invasion of Attu. Bombing and destruction of Adak, in most cases, would be conducted by the Second Mobile Force. In all other operations Plan No. 1 would be applicable."

There were several difficulties in making preparations and completing them by the end of May 1942. Mainly, the units which had been operating in the Indian Ocean Area and subsequently assigned to the Aleutian Operations did not return until late 1942. They were sent out, immediately, in an effort to locate and engage the Halsey-Doolittle Force. On return from this assignment (about the 28th of April 1942), it was necessary for these ships to be given thorough maintenance because they had been operating over a long period away from the maintenance facilities located on the Homeland, and, further, crews had to be reorganised. Thus, these ships had a major problem in getting ready to operate most efficiently for the Aleutian Operations.

In summary, the ships requiring thorough maintenance at this time included: the two heavy cruisers Takao and Maya: the two light fleet aircraft carriers Ryujo and Junyo: and the seven destroyers Nenohi, Hatsuharu, Wakaba, Hatsushimo, Hibiki. Ikasuchi

--34--

and Inazuma. Although the 20th, 24th and 27th Destroyer Divisions were basically assigned to support the Midway Invasion Force, and were also undergoing maintenance at this time, they were included in this group because they were scheduled to support the operations if the situation demanded. In addition, the three destroyers Ushio. Oboro and Akebono returned from the Battle of the Coral Sea, arriving at Ominato only a day before the scheduled date of departure for the invasion forces. Consequently, several of the commanding officers could not participate in the preliminary operational discussion and the war game.

Due to the fact that defensive installations at Akkeshi were inadequate to handle such a large force, and the difficulty encountered in obtaining an adequate supply of oil, the rendezvous point was changed from the Bay of Akkeshi to the Bay of Mutsu. Unexpected damage to the tanker Shiriya caused the difficulty in obtaining the necessary oil supply.

The Army North Sea Detachment was organized at Asahikawa on 9 May 1942, and departed just thirteen days later aboard the Navy transport Kinugara Maru and the destroyer Shiokaze. Upon arrival at Ominato on 23 May 1942, this detachment and the Maizuru Third Special Landing Force were placed under the command of Admiral Hosogaya.

The war game for the proposed Aleutian and Midway Invasion Operations was held on 29 April 1942, at Yokosuka, but as mentioned previously, only a few of the commanders who were to take part were

--37--

able to attend. Practice landing maneuvers for both Attu and Kiska began on 25 May 1942. There were independent training sessions commencing at this time for the various forces, and conferences were held regarding fleet operations. Again, some of the commanders were unable to attend these conferences as they had not as yet arrived at Ominato.

All things considered, for a naval force which was the protagonists in the most ambitious plan of the Imperial General Headquarters in the war, this was a precarious situation. But be that as it may, the operational preparations were considered as complete as possible, and the Aleutian Invasion Operation was underway.

--38--

CHAPTER V

Operations, Movements and Occupation

Development (General)

The day following the practice landing maneuvers (25 May 1942), elements of the invasion forces started moving out from Ominato. According to the prearranged plan, the Second Mobile Force moved out first on the 26th. The Main Body and the Kiska Invasion Force departed on the 28th, and the Adak-Attu Invasion Force departed on the 29th. Despite thick fog, stormy weather and supply difficulties, most units operated as planned.

On the 4th and 5th of June, the Second Mobile Force executed a fairly effective air raid on Dutch Harbor. On 5 June, the Adak-Attu Invasion Force changed course at the prescribed point, and headed for Adak. At the same time, the Kiska Invasion Force headed for Kiska.

Changes in the original plan were in the offing: On the 5th, the First Mobile Force which had been operating in the Midway Invasion fought the Main Strength of the enemy fleet and suffered heavy loses. At 0920 hours, 5 June 1942, Combined Fleet Operational Order Number 155 was issued, and directed the Second Mobile Force to join the First Mobile Force in the Midway Area. In an effort to fight a decisive battle, the Commander-in-Chief of the Combined Fleet issued Operational Order Number 156. just thirty minutes later, and committed the greater part of the Combined Fleet

--39--

to action.

The invasions of Midway and the Aleutians were temporarily postponed.

In complying with Combined Fleet Operational Order Number 156. the Second Mobile Force and the First Destroyer Squadron (elements of the First Fleet) directed their course toward Midway.

It was directed that the attack on the enemy fleet would be

carried out by employing Method "C". The "Attack Method 'C'" referred to in the Combined Fleet Operational Plan for the Midway

and Aleutian Invasions, issued on 12 May 1942. There were three

points in the "Method 'C' Plan":

"1. In the event the enemy fleet headed westward with a large body of ships, our entire fleet will fight a decisive battle according to the fixed plan of operations.

"2. The First Mobile Force will take command of the First and Second Mobile Forces. The Advance Force Commander will assume command of the First, Third and Fifth Submarine Squadrons.

"3. The elements of the First Fleet (which were maneuvering in the northern area) will rejoin the Main Force of the Fleet."

The Commander-in-Chief of the Combined Fleet ordered the attack against Midway to be abandoned at 2355 hours on 5 June 1942. At 0700 hours on the 6th, the Second Mobile Force and the First Destroyer Squadron were returned to the Northern Naval Force by Combined Fleet Operational Order Number 162 This order also reinforced the Northern Naval Force, and transferred the following unite from the Midway Area, effective on or after 8 June 1942:

--40--

Battleships: Kirishima and Hiei from the 3rd Battleship Division

Heavy Cruisers: Tone and Chikuma from the 8th Cruiser Division

Destroyers: Arashi, Hagikase, Nowake and Maikase from the 4th Destroyer Division

Seaplane Tender: Kamikawa Maru

Light Fleet Aircraft Carrier: Zuiho

This order was cancelled, however, on 8 June, and the Guard Unit from the Midway Invasion Force was substituted therefore. The Reinforcement for the Northern Naval Force was now as follows:

Battleships: Ise, Hyuga, Fuso and Yamashiro from the 2nd Battleship Division; Kongo and Haruna from the 3rd Battleship Division

Light Cruisers: Kitakami and Oi from the 9th Cruiser Division

Light Fleet Aircraft Carriers: Zuiho1

Destroyers: Amagiri, Yugiri, Asagiri and Shirakumo from the 20th Destroyer Division; Umikaze, Kawakaze and Yamakaze from the 24th Destroyer Division; and Ariake, Yugure and Shiratsuyu from the 27th Destroyer Division

Oilers: San Clemente Maru and Toa Maru (plus an escort

1. On 13 June 1942, the fleet aircraft carrier Zuikaku from the 5th Carrier Division was added.

--41--

destroyer for the oilers)

Heavy Cruisers: Myoko and Haguro from the 5th Cruiser Division2

Since the two operations were so closely related, Imperial General Headquarters revised part of the Army and Navy Central Agreement relating to the Aleutian Operations. It was decided to limit the invasion efforts to Attu and Kiska only. The Commander-in-Chief of the Combined Fleet was directed to revise his operations accordingly. Admiral Yamamoto issued an order to the Fifth Fleet Commander to that effect. The forces of the Fifth Fleet returned to their rendezvous, and the execution of the Aleutian Operation was modified with each force rescheduling its attack. There was a temporary delay as the original order issued directed the invasion forces to execute the operation according to Plan Number 5 (referred to on page 34) on N . 1 Day. The forces moved eastward under cover of the weather front which prevented anything but the most fragmentary and hazardous air reconnaissance. All operations proceeded smoothly, and the surprise landings on Kiska and Attu were executed successfully on 8 June 1942. These operations will be discussed in detail in the ensuing sections under: Details of the Second Mobile Force

Details of the Attu Invasion

2. These vessels were also added to the Northern Naval Force on 13 June.

--42--

Details of the Kiska Invasion

Details of the Main Body

Details of the Second Mobile Force

In actual operations, the Second Mobile Force was composed of the following ships, under command of Rear Admiral Kakuji Kakuda, commander of the 4th Carrier Division (see Chart No 6):

Heavy Cruisers: Maya and Takao

Light Fleet Aircraft Carriers: Ryujo (carrying 12 fighters and 18 attack planes), and the Junyo (carrying 18 fighters and 18 bombers)3

Destroyers: Ushio, Oboro, and Akebono

Oiler: Teiyo Maru

The Second Mobile Force sailed from Ominato at 1200 hours on 26 May 1942, and followed the course indicated on the Chart of the Aleutian Invasion Movements (see Map No 1). During the period from 26 May to 1 June, thick fog was encountered. However, two days before the opening of air operations, the weather gradually improved.

On 3 June, the radio direction finders indicated en enemy scout plane in the close vicinity of the force. Search precautions were taken by friendly planes, but the enemy plane was not located.

At 2400 hours on the 4th, the first assault unit for an air attack on Dutch Harbor was launched from a point about 180 miles

3. In addition to its own planes, the Junyo carried 12 fighters which were to have advanced to Midway after successful execution of the Midway Operation.

--43--

2D MOBILE FORCE

Chart No. 6

--44--

southwest of the target area. The unit was composed of three fighters and six attack planes from the Ryujo. and six fighters and twelve bombers from the Junyo. Weather conditions were most unsatisfactory; clouds hung low at a height between 200 and 300 meters. Visibility was poor, and it was impossible for planes to fly in formation. Therefore, each flying group had to act independently. On its way to Dutch Harbor, the group from the Junyo discovered an enemy patrol plane and shot it down. Due to the bad weather, this group turned back after progressing about half way to the target. The group from the Ryujo made the first single attack on Dutch Harbor. Though the weather was bad enroute, the sky over Dutch Harbor was clear. A group of oil tanks and a wireless station were bombed, and fighter planes strafed enemy flying boats in the anchorage. Results were below expectations, but the raid caused destruction of several oil tanks and a part of the wireless station.

As a result of photographic reconnaissance, it was discovered that Dutch Harbor was thoroughly equipped with various installations and effective anti-aircraft defenses. In the execution of this mission one of the planes was hit, and had to make a forced landing in enemy-held territory.

Five destroyers, which were discovered by reconnaissance planes, were anchored in Makushin Bay, northwest of Unalaska. An attack against these destroyers was attempted with all serviceable planes. Four reconnaissance seaplanes were also included in this

--45--

attack. Because of bad weather, however, the carrier planes turned back from the coast of Unalaska, and only the four seaplanes succeeded in penetrating as far as Makushin Bay. Before they could attack, though, they were met by about ten enemy fighters which shot down two of our planes. The other two were able to return, but sank immediately upon landing because of damages received. Though the four seaplanes were not able to make their attack, lt was revealed for the first time that an enemy land plane base existed in the Dutch Harbor area.

On the first day of action, our Mobile Force was tracked by enemy planes all day. Two of them were shot down. Because of the bad weather there were no enemy air raids launched at this time.

Following the return of the planes to their respective ships, the force withdrew toward the southwest. According to the plan, we re-fuelled during the night; and on the second day left from a spot southeast of Adak and carried out reconnaissance on Atka, and later conducted an attack against Adak. Due to the bad weather, the force was unable to cruise at a speed faster than nine knots. It was impossible to reach the prearranged point for launching an attack on Adak by the second day. In the west, it became apparent that weather conditions were going to become steadily worse. Thus, with this forewarning, it was decided to launch another air attack against Dutch Harbor immediately.

The force changed course, and headed toward Dutch Harbor. On the second day, five large enemy planes arrived over the force and

--46--

tried repeated attacks. Fighter planes shot down two of the enemy craft, and another was shot down by antiaircraft fire. There were some near misses by enemy planes, but no damage was suffered.

At about 1200 hours, 5 June, a reconnaissance plane from the Ryujo. which had taken off earlier to make a weather patrol, reported that conditions at Dutch Harbor were generally favorable and gradually improving. Immediately, three fighters and six attack planes were dispatched from the Ryujo. and six fighters and eleven bombers from the Junyo. All had well-trained crew members. Taking full-advantage of breaks in the clouds, excellent results were achieved in this attack on oil tanks, seaplane hangars and other installations at Dutch Harbor. On the return to its carrier, the group from the Junyo engaged more than ten enemy fighters northeast of Umiak Island. Eight enemy planes were reportedly shot down, four were confirmed. We lost one fighter and four bombers. Friendly planes spotted an enemy ground air base in the northeastern part of Umnak Island which revealed that there were still more secret bases west of Kodiak, a factor for which our forces were not readily prepared.

During this raid, an order was received from the Commander-in-Chief of the Combined Fleet instructing the Second Mobile Force to Join with the First Mobile Force which was now busily engaged in the Midway Operations. A report was filed in answer to this order stating that the Second Mobile Force would sail south at 1230 hours (5 June 1942), or as soon thereafter as it could collect the planes

--47--

attacking Dutch Harbor. The force refuelled in the area of latitude 4441' North and longitude 17620' East on the morning of the 7th. Following this, the force maneuvered to join the First Mobile Force. The position of the Second Mobile Force at 1200 hours on the 5th was 120 nautical miles southwest of Dutch Harbor, and the essence of time was most essential in reinforcing the Midway Operations.

By dusk, the Second Mobile Force sailed south. At 0700 hours on the 6th, Admiral Hosogaya directed the force to rejoin the Northern Naval Force ... the Battle of Midway was ended. The course was changed, and this force headed westward. Thereafter, the activities of the Second Mobile Force were carried out in the sea south of Kiska. Patrol actions were carried out, and fighters were dispatched for the defense of Kiska as enemy air attacks there intensified.

Details of Adak-Attu Invasion Force

As outlined in Chapter Three, there was meager intelligence information available which pertained to the enemy's situation in the Aleutians. Both Adak and Attu were about thirty miles long and better than twelve miles wide. The islands were mountainous almost to the shore-line with very little level land anywhere. And the soil was sterile with very few trees on the islands. It was believed that there was a wireless station, observatory and a garrison unit of unknown strength stationed on Attu. These two islands, along with Dutch Harbor and Kiska, were considered among the most important

--48--

in the Aleutian Archipelago because of their strategic locations.

With the original mission of destroying enemy military installations on Adak and then invading and occupying Attu, the Adak-Attu Invasion Force was organized on 12 May 1942 by direction of the Commander-in-Chief of the Combined Fleet. The detailed planning and assignment was made, however, by the Northern Naval Force Operational Order Number 24. Under command of Rear Admiral Sentaro Omori, the force consisted of the following (see Chart No 7).

Light Cruiser: Abukuma, designated as the flagship

Destroyers: Nenohi, Hatsuharu, Wakaba, Hatsuhimo and Shiokaze

Mine-layer: Magane Maru

Transport: Kinugasa Maru

Seaplane Tender: Kimikawa Maru

The Army North Sea (Hokkai) Detachment

The Army North Sea Detachment, commanded by Major Matsutoshi Hozumi, was comprised mainly of the 301st Independent Infantry Battalion, 301st Independent Engineer Company, and a service unit (or a total of 1,143 men). The detachment was transported on the Shiokaze and the Kinugasa Maru.

The Adak-Attu Invasion Force and assigned personnel assembled in Ominato on 23 May 1942. A practice landing was conducted, and operational preparations were completed prior to the scheduled departure from Ominato. At 1100 hours on 29 May, this invasion force sailed, following the route indicated on the Chart of Aleutian

--49--

ADAK-ATTU INVASION FORCE

Chart No. 7

--50--

Invasion Force Movements (refer to Map No 1).

The movement to the invasion point was rough due to the bad weather; fog was encountered every day. On the 5th of June, the force reached a location approximately 600 nautical miles southeast of Adak, It was at this point that an order was received suspending the Aleutian Operation temporarily, and instructing the First Destroyer Squadron to participate in the Midway Operations, The squadron started to move south. On the 6th at 1300 hours, however, instructions were received from the Northern Naval Force to resume the Aleutian Operations according to Plan Number 5 (see page 34), which cancelled the landing at Adak and to conduct only the invasion of Attu. The force moved toward this objective, and entered the prearranged anchorage at 2130 hours the following day.

Due to the density of the fog, it was most difficult to find the landing beach. However, a surprise landing was finally accomplished on the southern shore of Holts Bay at 0010 hours on 8 June. There was no enemy resistance, and advance was made immediately toward Chichagof. At 0720 hours, this objective was reached after travelling over a poor and steep road. This island was occupied without a struggle, and only two Americans and forty-five native inhabitants were found.

After the enemy had learned of our advance to the western Aleutians, counterattacks were launched against the invading forces by enemy planes and submarines. On the morning of the 9th, an enemy submarine attacked friendly transports in the southern sea off Attu,

--51--

but no damage resulted.

Following the occupation of Chichagof, the North Sea Detachment rushed the unloading of its equipment. On 11 June, following the completion of the unloading, emphasis was placed on developing defensive installations.

An enemy FBI seaplane appeared over Attu on the 12th, and enemy patrol planes appeared on several occasions after this. From all indications, the main forces of the enemy air corps were centered around Dutch Harbor and Umnak Island.

The First Destroyer Squadron Commander, acting on orders received from Vice Admiral Hosogaya, departed from Attu on the 13th to reconnoiter the Amchitka area. Rear Admiral Omori was instructed to find suitable sites for air bases. On the 15th at 0600 hours, this force, consisting of the light cruiser Abukuma, and four destroyers, arrived at Constantin Harbor, Amchitka Island, and conducted reconnaissance with a seaplane from the Abukuma and shore patrol parties. An enemy B-17 discovered the detachment and kept its operations under constant observation. With the report stating that there were not suitable sites for land air bases, operations were suspended and the force put out to sea just three hours later, and rejoined the Northern Naval Force.

On 21 June at 1100 hours, an enemy submarine attacked the Jujisan Maru, which was unloading aviation gasoline in the Chichagof area, but no damage was suffered. The Nenohi sank the submarine with a depth charge.

It was estimated that the enemy had advanced their bases to Atka and Kuluk Bay at Adak. After evaluating this conclusion, Vice Admiral Hosogaya was convinced that if Kiska and Attu were evacuated for the winter months, as was contemplated, any reoccupation by our forces in the following spring would be difficult; it was believed that the enemy forces would undoubtedly plan on occupying the islands. Imperial General Headquarters concurred with Admiral Hosogaya with the result that the Navy Section issued Directive Number 106 on 23 June, which stated that Attu and Kiska would be securely occupied, and that the capture of Adak would not be carried out.

On 25 June, the Army Section of Imperial General Headquarters issued an order establishing that, as of that date, the Army North Sea Detachment would be transferred from the command of the Fifth Fleet and placed directly under control of Imperial General Headquarters. Further, the detachment was to securely occupy Attu. Thus, it was established that Kiska and Attu were to be occupied permanently by the Navy and the Army respectively, and that reinforcements were to be provided.

On 3 July at 0840 hours, four enemy B-24s executed an hour-long bombing raid against the three vessels Kimikawa Maru, Kamikawa Maru, and Fuji Maru. all of which were anchored off of Attu. Only slight damage was suffered. However, on the 5th at 1300 hours, an enemy submarine torpedoed and sunk the destroyer Nenohi while the ship was cruising in the heavy fog. There were thirty-six survivors

--53--

who returned alive.

A reconnaissance made in the middle of July revealed that the enemy was using both Adak and Atka Islands as supply bases for their submarines. On 6 August, our flying boats raided the Atka area, but no enemy vessels were seen. Two P-39s were encountered and engaged above Nazan Bay. This revealed that the enemy had constructed an air base in that area.

Enemy fleet offensive activities increased about the beginning of August. On 8 August at 1500 hours, four enemy cruisers and ten destroyers attacked the southern part of Attu. After bombarding the area for thirty minutes, this force withdrew in an easterly direction. As a counter-measure to the increasing enemy air attacks, on 17 August the 32nd Independent Field Anti-aircraft Battery arrived to reinforce the defenses on Attu.

After 25 August, frequent appearances of enemy reconnaissance planes were noted over our newly won defenses. A constant alert was maintained. On 28 August, an enemy cruiser, destroyer and two flying boats were discovered in Nazan Bay. Enemy planes advanced as far as the coast of Attu and began attacking our transport vessels that were harbored there. On 30 August, the Navy transport Nichiryo Maru was strafed and bombed by enemy planes 140 nautical miles west northwest of Attu, but suffered little damage.

On 3 September, the submarine RO-62 observed five enemy cruisers and several destroyers sailing west 70 nautical miles west northwest of Atka. A strict alert was issued to the commanders of the Attu

--54--

and Kiska defense forces. Since the beginning of September, enemy action in the Aleutians had been greatly intensified.

On 1? September, the Army North Sea Detachment was transferred to Kiska as reinforcement in strengthening the defense of that island. This phase of the operations is covered in the next section.

On 1 October, an air reconnaissance report stated that the enemy was constructing a large 2,000 by 500 meter air base at Kuluk Bay on the east coast of Adak. According to this report, some twenty heavy bombers and thirty fighters were attached there.

On 30 October, the Yonekawa Unit of the Infantry Force of the North Chishima Fortress, consisting of two infantry companies, under the command of Lieutenant Colonel Hiroshi Yonekawa, reinforced the island of Attu. The Attu Sector Garrison with a part of the 51st Signal Unit was later organized for the defense of the island.

On 27 November, an enemy B-24 and eight other fighting aircraft bombed and disabled the 2,427 ton Army transport Hachosan Maru while the vessel was being unloaded at the quay. On 19 February 1943, between 0930 and 1130 hours, land installations were strafed and bombed by eleven enemy planes, but slight damage was suffered.

The over-all picture of the engagements and operations after occupation is discussed under subsequent chapters, as this particular phase of the operation encompassed all defensive measures established on the western Aleutians.

--55--

Details of the Kiska Invasion Force

The Kiska Invasion Force, under the command of Navy Captain Takeji Ono, consisted of the following (see Chart No 8):

Light Cruisers: Kiso (flagship) and Tama

Destroyers: Hibiki, Ikazuchi, Inazuma and Hokaze

Mine-sweepers: The 13th Minesweeper Division

Transports: Hakusan Maru and Kumakawa Maru

Converted Cruisers: Awata Maru and Asaka Maru

Converted Gunboats: Kaiho Maru, Hakuho Maru, and Shunkotsu Maru

13th Subchaser Division (3 subchasers)

The Maizuru Third Special Landing Force

The Maizuru Third Special lending Force, under command of Lieutenant Commander Hifumi Mukai, was aboard the two transports Hakusan Maru and Kumakawa Maru.

The Kiska Invasion Force departed from Ominato on 28 May 1942, stopping at Paramushiro for supplies on 1 June at 1800 hours. After refueling, the force again put out to sea at 1300 hours on the 2nd proceeding at ten knots following the course indicated on the Chart of the Aleutian Invasion Movements (refer to Map No 1).

The Midway Operation caused a temporary suspension of the invasion of the Aleutians which was originally scheduled for 6 June. At 0420 hours on the 6th, the Kiska Invasion Force changed course and cruised westward. At 1200 hours on the same day, an order was received setting the day for recommencing operations in the Aleutians

--56--

KISKA INVASION FORCE

Chart No. 8

--57--

as N + 1. Four hours later, the course was again changed, and the advance was resumed. The operation progressed as planned. Kiska was reached on the 7th at 2227 hours.

The Maizuru Third Special Landing Force made a surprise landing on the eastern shore of Leynard Cove. Within three hours, Kiska Harbor and other important points were occupied. There was no enemy resistance encountered. A landing unit selected from the crews of the Kiso and the Tama conducted a mopping-up campaign on Little Kiska Island.

The enemy was using both Adak and Atka as supply bases for their submarines.

On the afternoon of 12 June, the bow of the destroyer Hibiki was nearly destroyed as a result of an enemy air attack which consisted of five heavy bombers, escorted by a twin-engined flying boat and a four-engined flying boat. In the early morning hours of the 13th, the 6,800 ton Nassan Maru was sunk by enemy bombs in Kiska Bay.

On 13 June, one of the reconnaissance flying boats from the Toko Air Group reported observing an enemy seaplane tender and eleven flying boats in Kazan Bay on the east coast of Atka.

On 1 July, the Fifth Naval Garrison Unit was organized for the purpose of establishing and maintaining land defenses on the strategic island of Kiska. The Unit was composed of the Maizuru Third Special Naval Landing Force, one unit of the Special Submarine Base Force (six midget submarines, one hundred base personnel and two hundred and fifty construction personnel) and one Naval Construction

--58--

Unit (seven hundred fifty personnel). In addition, a Naval Land Artillery Force consisting of one cannon unit (12 c.m and 15 c.m.), one anti-aircraft artillery unit and one anti-aircraft machine gun unit, which was supposed to have been assigned for the defense of Midway, was allocated to the Fifth Naval Garrison Unit.

On 5 July at 0300 hours, enemy submarines torpedoed the Arare, the Kasumi and the Shiranuhi which were harbored at the entrance of Kiska Bay: The Arare was sunk and 104 men were killed; the Kasumi was severely damaged and 10 were killed; and the Shiranuhi was partially destroyed and 3 were killed. All of these vessels were guarding the submarine tender Chiyoda. which was anchored in the harbor. Another enemy submarine attack occurred at 1130 hours on the 15th, and the submarine chasers Numbers 25 and 27 of the 13th Submarine Chaser Division were sunk while they were sweeping the sea off Kiska Bay. Again, on the 31st at 0700 hours, an enemy submarine appeared off the bay and torpedoed the Kano Maru, causing partial damage.

On 6 August, our flying boats raided the Atka area, but no enemy vessels were seen. Two enemy P-39s were encountered and engaged above Hasan Bay. This revealed that the enemy had constructed an air base in the immediate locale.

Enemy fleet offensive activities increased about the beginning of August. On the 8th at 1500 hours, four enemy cruisers, ten destroyers (including two large-type) bombarded defensive land installations, but slight damage was inflicted. On the morning of 15 September,

--59--

twenty fighter-type aircraft and seven bombers attacked friendly vessels which were in anchorage off Kiska Bay. The Nojima Maru was severely damaged, and the submarines RO-63 and RO-68 were slightly damaged as a result of this bombing raid. On 7 October, another air raid, consisting of sixteen fighters and nine bombers attacked, and stranded the Army transport Borneo Maru. Ten days later, seven enemy bombers attacked and sunk the Oboro and disabled the Hatsuharu: both vessels were anchored in Kiska Bay at the time.

The Fifth Air Group was organised on 15 August 1942, and comprised twelve fighter seaplanes. On 1 November, this Air Group was redesignated the 452d Naval Air Group, and its strength was increased to sixteen fighter seaplanes.

As of 25 August, the Army North Sea Detachment, stationed on Attu, was ordered to Kiska to reinforce the defense there. This concentration of all. Navy and Army forces on Kiska, was put under the command of C in C, Fifth Fleet. Originally, Imperial General Headquarters had planned on withdrawing the troops from Kiska and Attu during the winter months, but there were many indications that Kiska would be invaded by enemy forces. If this happened, it would cause a critical situation for the naval garrison then consisting of only 500. As an emergency action, the 1200 Army troops on Attu were transferred temporarily to this strategic island as reinforcements.

On 15 September, the 51st Naval Base Force was organised in order to establish a more effective operational command (see Chart

--60--

Chart No. 9

--61--

No 9). This force consisted mainly of naval forces already stationed there and also included the Army North Sea Detachment. Later, on 6 October the 22nd and 32nd Independent Field Anti-Aircraft Batteries were added to the strength of Kiska.

All in all, the defenses of this strong-hold were shaping up. Kiska defensive areas were linked by a fairly well-developed road net; and by the end of October, enemy air attacks on Kiska decreased. After the 26th, the enemy neither strafed nor bombed when they flew over the island with very few exceptions. Development of Kiska was much more extensive than was the development of Attu.

By the 1st of November, a Central Agreement Between the Army and the Navy regarding the strengthening of defenses in the western Aleutians was published. This agreement included several important points to combat the enemy in future defensive measures and operations. In substance, this agreement stated:

"The objective of the operations is to strengthen defenses in the area through supplying the required land forces, and to reinforce and make secure the key points in the western Aleutian Islands throughout the winter. . .

"The Fifth Naval Fleet and the North Sea Garrison (formerly the North Sea Detachment plus reinforcements) will be used as the military strength. . .

"Special emphasis will be given to the strengthening of defense in the key areas surrounding Kiska and Attu with Semichi as the center. Every effort will be made to complete defenses by February 1943. . .

"A unit composed of two infantry companies will be organised from the fortification units located in the North Kuriles, and will be dispatched as quickly as possible to Attu as reinforcements and secure the island. . . Two infantry battalions

--62--

assigned to the North Sea Garrison will advance to Kiska and. Attu as reinforcements. At the earliest practical time, they will occupy Semichi Island. If additional troops are necessary, they will be supplied to the North Sea Garrison Unit . . . Depending upon the situation as it develops in the process of strengthening the defense of Kiska, the occupation of Amchitka may be ordered. Before proceeding with the occupation of Amchitka, Imperial General Headquarters will make the decision taking into consideration all phases of the operation.

"Air bases will be established first at Semichi and Kiska. A seaplane base will be set up near Kiska and Attu. The Army will be primarily responsible for the construction of air bases, but will be assisted by the Navy. The transfer of planes to the advance air bases will be agreed upon at a later date . . .

"Urgent transportation of troops for Attu and the North Sea Garrison will be carried out by Navy ships in the most part. Munitions and supplies will be carried by Army transports, escorted by Navy vessels. They might, however, be transported by naval vessels depending on the enemy's situation at the time.

"Land defense units and anti-aircraft units at Kiska will be under the unified command of the senior commander there. The North Sea Garrison will be placed again under the operational command of the Fifth Fleet Commander. The latter will also decide the system of communications."

With reference to the carrying out of the provisions of this agreement, Major General Mineki, Commander of the North Sea Garrison conferred with Rear Admiral Akiyama, Commander 51st Base Force, at Kisuka on 10 November. It was decided that in order to complete general defensive measures by the end of February 1943, the transportation of necessary goods and personnel had to be stepped-up, and furnished no later than early December. This recommendation was forwarded Imperial GHQ. (Also see Chapter Seven - Transport -Escort Operations.)

--63--

Details of the Main Body

The mission of the Main Body was to support the entire Aleutian Operation. After the successful occupation of Kiska and Attu, the Main Body was afloat in the area south of Attu, directing the Operation and standing in readiness to meet enemy forces.

As of 20 June 1942, Admiral Hosogaya directed the Third Distribution of his forces including the deployment of reinforcements which has been sent by the C in C, Combined Fleet. Most of the strength of the original complement, less the seaplane and submarine units, was directed to return to Ominato to reorganise and receive further instructions. This was according to plan.

On 25 June, the Main Body of the Northern Naval Force, including the reinforcements from the Combined Fleet arrived at Ominato to make arrangements for future operations. Upon completing necessary preparations for a possible enemy surprise attack, the Main Body sailed from Ominato, and assumed operational alert positions in the area southwest of Attu. A part of this mission was to escort the transports carrying troops and supplies for the reinforcement of Kiska.

Unexpectedly, no enemy sea activity occurred, and on 7 July, C in C, Combined Fleet directed that moat of the vessels, then operating in the northern area were to be returned to the western part of the Inland Sea to prepare for further operations. Accordingly, in the rearrangement of naval forces carried out as of 10 July, the following vessels were reassigned from the command of the Fifth

--64--

Fleet to other missions:

Battleships: Kongo and Haruna of the 1st Section of the 3rd Battleship Division

Fleet Aircraft Carrier: Shokaku of the 5th Carrier Division

Light Fleet Aircraft Carrier: Ryujo of the 4th Carrier Division

Heavy Cruisers: Takao and Chokai of the 2nd Section of the 4th Cruiser Division; Haguro and Myoko of the 5th Cruiser Division; Tone and Chikuma of the 8th Cruiser Division

Destroyers: Arashi, Hagikase, Nowake and Maikase of the 4th Destroyer Division: Akebono, Ushio and Sazanami of the 7th Destroyer Division; Akigumo, Yugumo, Makigumo and Kazagumo of the 10th Destroyer Division and Urakaze

Also, most of the Transport Group was directly attached to the Combined Fleet for centralized control.

As a result of this reorganisation, the Fifth Fleet was reduced to the following ships and units under command of Vice Admiral Hosogaya:

Heavy Cruiser: Nachi (flagship)

Light Cruisers: Kiso and Tama of the 21st Cruiser Division; Abukuma of the 1st Destroyer Division

Destroyers: Wakaba, Hatsushimo, Oboro, Ikazuchi, Inazuma Hibiki and Ikatsuki of the 1st Destroyer Squadron (6th and 17th Destroyer Divisions)

--65--

Submarines: I-1 through I-7 from the 2nd Submarine Squadron

Submarine Tenders: Chiyoda and Argentine Maru

Seaplane Tender: Simikawa Maru (with 8 three-seater reconnaissance planes on board)

Six flying boats from the Toko Air Group Detachment

Garrison Units for the defense of Attu and Kiska

Organization chart showing the strength of the Northern Naval Force as of 10 July 1942 is included on Chart No. 10.

On 7 July, Admiral Hosogaya returned to Yokosuka for necessary supplies and maintenance. Upon observing no change in the situation, he also directed the remainder of his forces to return to the bases Yokosuka, Ominato and Maizuru for the same reasons.

Following conferences with the Navy Section of Imperial General Headquarters and the Combined Fleet held at Yokosuka, Admiral Hosogaya returned to his base of operations at Ominato where he directed the Northern Forces. In the meantime, the Main Body returned to their advanced bases after completing necessary resupply and maintenance. Finally, enemy task forces appeared in the Kiska and Attu areas on 7 August. Admiral Hosogaya led the Main Body from Paramushiro to the sea south of Kiska, but did not encounter the enemy so returned to Ominato again adopting the policy of watchful waiting.

On 28 August, a report was received stating that an enemy fleet appeared near Nazan Bay, Atka Island. The air units on Kiska were ordered to make an attack. At 2000 hours on the 29th, the Main Body

--66--

--67--

moved out from Ominato, and by 3 September had advanced to a point 650 nautical miles southwest of Kiska. At the same time, the 21st Cruiser Division and the 1st Destroyer Squadron left Paramushiro, and advanced to the area southwest of Attu. Neither element encountered the enemy, so again returned to Ominato.

By the end of October, the Main Body reassembled at Paramushiro and completed preparations for the reoccupation of Attu. The ships and Army personnel involved were dispatched for Attu. This force, consisting of the Abukuma, Kiso, Tama, Wakaba, Hatsuharu with the Tonekawa Army Unit aboard, was supported by the Nachi. Attu was reoccupied on 30 October without resistance.

On 10 November, 545 men, including members of Headquarters, North Sea Garrison, aboard three destroyers and two transports, were sent to Kiska. On 3 December, an additional 570 men were transported to Kiska by the Abukuma, Kiso and Wakaba.

The Main Body remained in Mutsu Bay to assist in the overall operations of the Third phase of the Aleutian Operations. An advance transport unit was stationed at Paramushiro to handle vital supplies to Attu and Kiska and every effort was made to strengthen the defensive positions on the Aleutians. However, transportation to this area was extremely difficult due to the severe winter weather and the intensification of enemy air attacks.

4. The Yonekawa Army Unit referred to was composed of forces mentioned in the Joint Central Agreement of 1 November 1942, making the organisation a matter of record in the chain of command process.

--68--

On 24 January 1943, an air reconnaissance reported that the enemy had advanced to Amchitka. Immediately, the Northern Naval Force Commander ordered air forces and submarine squadrons to attack enemy ships which were supplying these advanced bases. The situation became so critical that Admiral Hosogaya took, his flagship, the Nachi, to seek-out and engage the crafty enemy. No contact was established, however, and he returned to Paramushiro.

Information made available at the time this monograph was written revealed that during the period from July to December 1942 the Submarine Force consisted of the following: From July to August, six submarines from the Second Submarine Squadron supported the Aleutian Operation. From August to November, seven submarines of 27th and 33rd Submarine Division, were attached to the Fifth Fleet. And, since December, two submarines, I-34 and I-35, were attached to the Fleet. This primary mission of the underwater boats was that of patrolling and scouting, and attacking strategic enemy targets. Other than these mentioned submarines, six midget submarines were assigned to the Kiska base. These midget submarines, however, were never used in action because of the lack of necessary facilities in Kiska, as well as the bombing attacks by the hostile planes.

The enemy's occupation of Amchitka in mid-January 1943, like their occupation of Adak five months before, permitted an immediate acceleration of bombing and reconnaissance missions over Kiska and Attu. Within two months, efforts were abandoned to bring supplies by surface vessels into these strong-holds.

--69--

The closing phases of the Aleutian Operation are discussed in Chapter Eight. However, it may be mentioned at this time that the tactical surprises such as the establishment of enemy air fields west of Kodiak (a factor for which our forces were not prepared), plus the reverses at Midway, induced the final withdrawal from the western Aleutians.

--70--

CHAPTER VI

Summary of the Operations

Synopsis of Aleutian Invasion Force Movements (May - June 1942)

I. The Adak-Attu Occupation Units departed from Ominato (Point "A") on 29 May 1942, taking the course as shown on Map No. 1 (page 35), and reached Point "B" on 5 June. Shortly thereafter, orders were received from the Combined Fleet directing a change in course towards the north to Adak; and join the First Fleet already engaged in the Midway Operations. Then, while diverting southward, Combined Fleet orders were received to rejoin the Northern Naval Force. Taking a course due north, a tanker was met at Point "C". After refueling, a northwest course was followed. Holts Bay (Point "D") was reached by 2130 hours on 7 June. The day following at 0010 hours, embarkation of the Army unit was completed, and advance was made by land route. Chichagof Bay was occupied by 1130 hours on the same day. No enemy resistance was encountered. After the successful completion of this mission, orders were received to reconnoiter Amchitka for suitable locations for an airfield. A force departed from Attu on 13 June, and reached Amchitka (Point "E") at 0600 hours on the 15th. After reconnoitring the Constantino Bay area, the reconnaissance party departed just three hours later after being spotted by an enemy B-17. The vessels stayed in readiness on the ocean south of Kiska up to the time they returned to Ominato on 25 June.

--71--

II. The Kiska Occupational Force departed from Ominato on 28 May 1942 taking the course as shown on Map No. 1, and arrived at Shimushu (Point "F") four days later. On 2 June, after necessary refueling was accomplished, this force departed for Kiska. On 5 June, orders were received from the Combined Fleet to suspend the attack. A turn-about-run was made (Point "G") until further instructions were received on the 6th to resume the attack. After the second turn-about was accomplished, this force reached Kiska Harbor (Point "H") at 2100 hours on the 7th. At 2330 hours, the occupational force landed without resistance. Following the successful completion of this mission, the escort force mainly stood ready on the sea south of Kiska for security reasons. Later, these vessels returned to Ominato together with the other forces on the 25th of June.

III. The Second Mobile Force departed from Ominato on the 26th of May 1942, and advanced as shown on Map No. 1. On 4 June, this force raided Dutch Harbor and Maxine Bay on Unalaska (Point "I"). With the exception of one part of this attack, it was unsuccessful because of the bad weather. Early in the morning of the 5th, a raid was planned on Adak (Point "J"), but again due to inclement weather this was not accomplished; however, the mission was diverted to raiding Dutch Harbor again. Thereafter, this force in taking necessary precautionary measures stayed in readiness on the sea southwest of Kiska.

--72--

CHAPTER VII

Transport and Escort Operations

The most difficult phase of the Aleutian Operations was the protection of transport movements. The causes were heavy fog, rough sea, enemy air and naval attacks, especially enemy submarine activities and mistakes in calculating the construction of air bases.

Development of land bases and completion of defensive positions were seriously hampered as a result of these difficulties. Actually, the land air bases were never completed. Consequently, enemy planes operated freely, and our forces held only very inadequate defense against enemy counterattacks. Finally, any continuation of supply transport became impossible. In turn, the food supply became critical. This, combined with the inadequate land defenses, created a most unfavorable position which eventually resulted in the withdrawal from the western Aleutian Archipelago.

During the initial stages of the invasion and occupation, transportation was carried out smoothly by transports which were adequately protected by a fleet which had numerical advantage. However, on 12 June 1942, the destroyer Hibiki bombed and sunk by enemy planes, as was the oiler Nissan Maru on the 19th. Friendly transport and escort ships suffered additional damages. On 5 July, at the entrance to Kiska Bay, enemy submarines torpedoed three destroyers of the 18th Destroyer Division, sinking the Arare, and

--73--

greatly damaging the Shiranuhi and the Kasumi. On the sane day, the destroyer Nenohi was sunk off Kiska as the result of a submarine attack. The intense enemy air and fleet action forced the withdrawal of all ships from Kiska to the northern Kuriles. This movement was completed on 11 October with the departure of the Sanpuku Maru.

The Imperial General Headquarters reaffirmed the necessity of securing the strategic points as planned in the western Aleutians. A plan of operations was issued directing that air bases and air superiority was to be maintained, and to oppose enemy air forces in the Aleutian area to the fullest extent. It was mandatory that the vital supplies be routed without interference. Necessary task forces were held in securing command of the sea, and emphasis was placed on the escorting of supplies. In addition, it was planned to establish strong bases on Attu, Kiska and Semichi, completing these defenses by February of 1943.

Transportation was further hindered, however, because the enemy counterattacks on the western Aleutians became even more intensified. The vessels harbored off Kiska were attacked almost daily, starting with the first part of October.

After the commanding general of the North Sea Garrison, Major General Mineki, landed on Kiska, he consulted with the commander of the 51st Base Force, Rear Admiral Akiyama. As previously mentioned in Chapter Five (pages 62-63), General Meneki advocated that in order to complete general defensive measures by the end of February

--74--

Attached as Chart No 11 is a brief resume of the scheduled sailings of vessels departing from Horomushiro for the western Aleutians covering the period from 1 November 1942 to 11 February 1943.

As a result of the experiences encountered during this period commencing with 1 November, it was decided by early January that several changes from the original plan had to be made. First, the cargo destined for Kiska, which was scheduled to be delivered by the end of August, would have to be completed by at least the middle of February; the cargo for the four subsequent months (approximately 40,000 tons) would have to be completed by the end of March. Second, highspeed vessels capable of traveling more than twelve knots per hour would have to be used on these voyages. (Note: This decision was based on the sinking of the Montreal Maru and the Kotohira Maru by enemy planes.) And, finally, personnel, arms and other vital material were transported by warships.

--76--

SCHEDULE FOR TRANSPORTATION TO WEST ALEUTIANS ISLANDS

(1 Nov 42 to 11 Feb 43)

TRANSPORTATION SCHEDULE

REMARKS

DESTINATION

VESSEL

DEPARTURE DATE (from Paramushiro)

ARRIVAL DATE

LOAD

Semichi

DOVER MARU

DAIRIN MARU

Early Nov 42

Elm of 303d Bn AA, etc

Transportation suspended and destination changed to Attu

Attu

Same as above

Same as above

12 Nov 42

Arms, Ammunition and provisions_

Transportation completed

Attu

CHERRYBOUNE MARU

11 Nov 42

17 Nov 42

Arms and clothing

Stranded by hits from a heavy bomber and three light bombers a few hours after entering port.

Semichi

MONTREAL MARU

YAHATA MARU

24 Nov 42

Main strength of 303d Bn

Ordered suspension of occupation of Semichi on 20 Nov: returned to Kashiwabara on 2 Dec.

Kiska

ABUKUMA

KISO

WAKABA

30 Nov 42

3 Dec 42

Main strength of 302d Bn

Transportation completed

Attu

KOAN MARU

28 Nov 42

Fuel, construction material and provisions

Postponed.

KIMIKAWA MARU

10 Dec 42

Kiska

2 Army Transports

13 Dec 42

Elm of 303d Bn., ammunition and provisions

It was planned to complete the transportation to Kiska by end of December; however, this plan was

changed due to disaster of the CHERRYBOURNE MARU at Attu.

3 Army Transports

17 Dec 42

URAJIO MARU

NISHIYU MARU

25 Dec 42

Transportation temporarily suspended until arrival of fighter seaplanes.

Attu

KIMIKAWA MARU

19 Dec 42

25 Dec 42

7 fighter seaplanes

Attu

KOAN MARU

24 Dec 42

29 Dee 42

Provisions, aviation fuel

Left port before unloading entire cargo.

YAMAYURI MARU

24 Dec 42

29 Dec 42

Arms, provisions, construction materials and coal.

URAJIO MARU

21 Dec 42

30 Dae 42

303d Indep Engr

Transportation completed. Both

 

Attu

KIMIKAWA MARU

19 Dec 42

25 Dec 42

7 fighter seaplanes

Attu

KOAN MARU

24 Dec 42

29 Dec 42

Provisions, aviation fuel

Left port before unloading entire cargo.

YAMAYURI MARU

24 Dec 42

29 Dec 42

Arms, provisions, construction materials and coal.

Kiska

URAJIO MARU

21 Dec 42

30 Dec 42

303d Indep Rngr Bn., provisions and dismantled housing materials

Transportation completed. Both vessels attacked by enemy planes on two occasions. URAJIO Maru damaged by torpedoes.

NICHIYU MARU

23 Dec 42

28 Dec 42

MONTREAL MARU

29 Dec 42

Elm of 302d Bn and 302d Indep Engr Bn

Postponed

NITTEI MARU

6 Jan 43

Naval materiel

Transportation completed

MONTREEL MARU

Jan 43

Elm of 302d Bn and 303d Indep Engr Bn. Airfield materiel

Sunk at 0700 hours, 6 Jan 43 near Komandorskie Island after being attacked by enemy planes.

Attu

KOTOHIRA MARU

31 Dec 42

Provisions, dismantled housing materials and fuel.

After being attacked by enemy planes, sunk at a point 8 kilometers northeast of Attu Bay, 0900 hours, 6 Jan 43.

Kiska

MELBOURNE MARU FUJIKAGE MARU

5 Jan 43

17 Jan 43

Elm of 302d Bn and naval materiel

Transportation completed. Both vessels attacked twice by enemy planes on 19 Jan 43 but suffered no damage

SAKITO MARU

KIMIKAWA MARU

25 Jan 43

31 Jan 43

Naval materiel

Transportation completed

ASAKA MARU

30 Jan 43

4 Feb 43

Naval materiel

Transportation completed

MELBOURNE MARU

Early Feb 43

Arms, ammunition and provisions

Suspended

Attu

AKAGANE MARU

30 Jan 43

3 Feb 43

Naval materiel

Transportation completed.

Remarks: 1. As of 5 Jan 43, it was perceived that the transportation schedule which was to be carried through until August could be accomplished by the middle of February and that the four months' (Sep to Dec) transportation of 40,000 tons could be completed by end of March.

2. As of 7 Jan 43, as a result of the losses of the MONTREEL Maru and the KOTOHIRA Maru, transportation was carried out by ships having speed of 12 knots or better.

3. As of 8 Jan 43, plan was changed in which personnel, arms and other equipment were transported by warships.

Chart No. II

CHAPTER VIII

Withdrawal Operations

Causes Leading up to Withdrawal

The deciding factor in the successful execution of the Aleutian Operation rested with the air forces. The Imperial Forces were inferior to the enemy on two deciding counts: First, the misjudgment in the construction of air bases; and, Second, insufficient air base construction power. These two serious defects hindered the completion of land-defenses in the western Aleutians.

In brief, the result was that the Japanese could not counter the activities of enemy aircraft, submarines and surface vessels. Due to the lack of air superiority, advance bases could not be constructed and ships could not properly discharge vital cargo. It finally became impossible to successfully occupy the Aleutians. The bases were subsequently forced to withdraw from Kiska leaving the area undefended against enemy planes.

On 24 January 1943, the enemy had established a naval air base on Amchitka, and, then, violently attacked Kiska and Attu from bases on Kuluk and Constantine. In this way the enemy cut off the transportation route to both of these islands; and from all indications made plans to retake this strong-hold.

About the middle of February, the enemy's North Sea Fleet, consisting of one cruiser, two light cruisers and six destroyers, began reconnoitring the waters off Kiska and Attu. They bombarded Attu,

--79--

and also sank the Akagane Maru in the waters west of Attu.

As previously outlined in Chapter Five, there were some 3.000 troops garrisoned on Kiska, while 2,800 defended Attu. It was, therefore, necessary to conduct operations in escorting transport Teasels to these islands, and at the same tine make plans to annihilate the enemy fleet. As it was impossible for slow vessels to engage in transportation without escort, a convoy of the Northern Naval Force succeeded in completing the first transportation mission since the turn of the year to Attu in early March 1943.

Sea Battle off Komandorskie

In carrying out the vital escort-transport operations for the western Aleutians, a sea battle off Komandorskie resulted on 27 March 1943. The forces that participated in this battle were as follows:

The Main Force, commanded by Vice Admiral Boshiro Hosogaya, commander of the Fifth Fleet and Northern Naval Force at that time, consisted of the flagship Nachi. the heavy cruiser Maya, the light cruiser Tama, and the two destroyers Wakaba and Hatsushimo. This force participated in the entire operation from 22 March to 28 March.

The Escort Force, commanded by Rear Admiral Mori Tomoichi, commander of the First Destroyer Squadron, directly escorted the convoy of the converted-cruiser Asaka Maru, and the Sakito Maru. This force consisted of the light cruiser Abukuma, the 6th Destroyer Division, Inazuma and Ikazuchi.

The Second Escort Force, which directly escorted the Sanko Maru, consisted of the destroyer Usugumo.

Upon approaching the destination, the enemy fleet was sighted

at about 0300 on the 27th of March. The Nachi, Maya, Tama and the

--80--

First Destroyer Squadron, in that respective formation, cut off the enemy's route of retreat, and at 0342 hours opened fire. Approaching from the windward side, friendly forces closed on the enemy to a distance of 14,000 meters. The enemy laid a smoke screen, dispersed and retreated. They were pursued for about four and a half hours, but to no avail. About this time, by radio interception our fleet knew that enemy planes had left their bases. With armor-piercing ammunition practically exhausted, and with fuel running low, the pursuit was discontinued about an hour later. Between 0915 and 1105 hours, the convoy of friendly transports was attacked by a small number of enemy planes but the attack was repulsed. At 1305 hours, the convoy reassembled and abandoned its mission; and returned to Paramushiro by 0800 hours on the 28th,

Our forces inflicted damages on one enemy heavy cruiser, one light cruiser and two destroyers; whereas, with the exception of the Nachi (which was hit five times and suffered the lost of 14 men killed and 27 injured), there were no other losses.

Vice Admiral Boshiro Hosogaya was relieved of the command of the Fifth Fleet and the Northern Naval Forces on 1 April 1943, and was replaced with Vice Admiral Shiro Kawase.

While repair and maintenance of the Main Body of the Fifth Fleet was being carried out on the vessels of the Fifth Fleet, enemy forces landed on Attu on the 12th of May. Immediately plans were made to utilize the entire Fifth Fleet in an attempt to recapture the island. However, preparation difficulties and unfavorable

--81--

weather prevented the execution of this operation. Also on 21 May it was decided to withdraw all forces from the Aleutians to the northern Kuriles.

Defeat and Withdrawal from the Aleutians.

On 29 May 1943, it was reported that the Attu Garrison was wiped out and the enemy forces bad occupied the island. Powerful enemy striking forces based on Hawaii and Dutch Harbor supported their operations. It was anticipated that a surprise attack would then be launched either against our fleet or a possible assault on northern Japan and the main islands. In addition, enemy submarines appeared east of Honshu as well as in the Kuriles area.

It was finally decided to withdraw the 51st Base Force and the North Sea Garrison, both under command of Rear Admiral Katsuzo Akiyama, to the north Kuriles area by early June. The recently appointed commander of the Fifth Fleet, Vice Admiral Shiro Kawase, decided initially to carry out this movement by submarine transportation. There were thirteen submarines engaged in this operation: I-9, I-34, I-155; 1st Submarine Division (I-21 and I-24); 7th Submarine Division (I-7 and I-2); 12th Submarine Division (I-175 and I-169); and the 19th Submarine Division (I-156 and I-157).

On 27 May 1943, the I-7 completed the first Journey. Contact was lost with the I-24 and I-9 which were both scheduled to discharge vital cargo at Kiska by the 13th or 14th of June. On the 22d, the I-7 was engaged with enemy warships and was sunk.

--82--

It was about this tine that it was decided to suspend transporting operations by submarine, and on 23 June, orders were received directing the submarines engaged to return to their respective bases. Thus, the first phase in the Withdrawal Operations came to an unsuccessful conclusion. During this period, however, there were some 820 Army, Navy and civilian employees transported from Kiska to the northern Kuriles, while only a few supplies consisting mainly of arms, ammunition and provisions were unloaded on Kiska.

Since the Withdrawal Operations from Kiska by means of submarine were abandoned, it was decided to attempt a mass withdrawal from this last strong-hold in the Aleutians by one single operation employing every available cruiser and destroyer assigned to the Fifth Fleet. The greater part of this force, under command of Vice Admiral Kakase, departed from Paramushiro on 7 July with plans to evacuate the personnel stranded on Kiska by the 11th. This operation was suspended, however, due to the unfavorable weather.

In the meantime the enemy rapidly established a seaplane base on Attu, and began reconnaissance raids over our northern defense area. On 19 July, the first of a series of raids commenced from established bases on Attu, Kuluk and Amuchitka. With the enemy making constant attempts to reduce the morale and fighting strength of the garrison forces with these aerial attacks, together with enemy patrol vessels circumventing Kiska, our supply line to the island was soon out off. The Withdrawal Operations from Kiska became

--83--

increasingly more difficult.

Finally, on 22 July at 2010 hours, the rescue force started out to make one last all-out attempt to evacuate the remaining troops on Kiska. It was planned to penetrate the enemy's encirclement of Kiska with one sweep from about 500 nautical miles southwest of the island, operating as far as possible beyond the range of enemy air power, which was by this time based on Attu and Amchitka. With favorable weather the garrison personnel were soon to be evacuated, and under cover of night retire to the southwest. Being outside the range of enemy air power, the plan was then to proceed west returning to Paramushiro,

On 26 July, the Kunajuri and the Abukuma collided in the thick fog, and in attempting to avoid this collision the Hatsushimo rammed the Wakaba and the Naganami. The Wakaba and the Hatsushimo were forced to withdraw from the operation because of damages suffered by this mishap. The Wakaba returned to Paramushiro for repairs, while the Hatsushimo managed to recover and escort the Nihon Maru.

At 0700 hours on the 29th of July, the combined units deployed Just fifty miles south of Kiska, and began infiltrating through the enemy's encirclement. By 1340 hours, the combined force was anchored off Kiska. Less than an hour later, all of the remaining personnel were embarked, and the force departed as planned for Paramushiro, arriving there by the 1st of August. The equipment used in defending Kiska was almost entirely destroyed by our defend-

--84--

ing forces prior to the evacuation.

Thus, ended our control of the western Aleutians. The situation in the North Pacific had been reversed within a period of less than fifteen months. . . The Aleutian Operation was ended.

--85--