Japanese Monograph No. 79A


JAN 42-MAY 42










Japanese Research Division


JAN 42-MAY 42



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, AFFE.

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.



This monograph presents a brief record of landing operations as well as Navy supported invasions in the Southwest Pacific Area from January through May 1942. In chronological order it covers participation in the invasions of the southern Philippines and northern Sumatra, the occupation of Christmas Island, and the invasions of Dutch New Guinea and the Lesser Sunda Islands. The material contained herein is based on the memory and personal papers of Commander Sakuo Mikami, former staff officer of Imperial GHQ charged with the planning and carrying out of these operations

Related monographs covering operations in this area are:

Mono No 66 - Java Operations Record, Part I: 16th Army

Mono No 67 - Palembang and Bangka Island Operations Record

Mono No 79 - Burma and Andaman Invasion Naval Operations, March 42 - April 42.

29 June 53




Mopping-Up Operations in the Philippines Area January - May 1942


Occupation of Northern Sumatra


Occupation of Christmas Island


Invasion of Dutch New Guinea


Operations in the Lesser Sunda Islands


Areas of Responsibility Southwest Pacific, May 1942



Following Page

Map 1

Northern Sumatra Invasion Operation, 8-13 Mar 1942


Map 2

Christmas Island Invasion, 29 to 31 March 1942


Map 3

Invasion of Dutch New Guinea, 29 Mar - 21 Apr 1942


Map 4

Lesser Sunda Islands Mopping-up Operation 9 - 16 May 1942


Map 5

Division of Areas of Responsibility Southwest Area Fleet, 1 May 1942



Following Page

Chart 1

Organization of 3d Southern Expeditionary Fleet 1 March 1942


Chart 2

Elements 1st Southern Expeditionary Fleet Used in Support of Northern Sumatra Invasion


Chart 3

Naval Forces Employed for Dutch New Guinea Invasion 15 March 1942



Following Page

Chart 4

Organization of Naval Forces in the Southwest Area (1 May 1942)




Mopping-Up Operations in the Philippines Area

January - May 1942

On 3 January 1942, following the early successes of the Japanese forces in the Philippines, Imperial General Headquarters issued Navy Directive No 38 pertaining to defense of the newly won territory. This directive assigned to the Navy the responsibility for the defense of the surrounding ocean areas as well as Navy shore installations and airfields. To carry out the sea defense, to protect the lines of communication, and to assist the Army in operations in remaining parts of the islands, the 3d Southern Expeditionary Fleet was organized. (Chart 1) From early January through 10 May, with the final surrender of organized American and Filipino forces on Mindanao, the 3d Southern Expeditionary Fleet assisted the 14th Army in the battles for Bataan and Corregidor, as well as the landings at Calapan on Mindoro Island and Kotabato and Cagayan on Mindanao Island.

Occupation of Northern Sumatra

The main body of the Imperial Guard Division operating under 25th Army was made responsible for the invasion and occupation of central and northern Sumatra. The C in C, 1st Southern Expeditionary Fleet was assigned the responsibility for escorting the division from Singapore to its landing points in Sumatra, with actual escort duties being carried out by the combat elements of the Fleet previously known

Chart 1


as the Malay Force.1 For this operation these same forces were redesignated the Northern Sumatra Invasion Force. (Chart 2 )

In outline, the invasion plan called for one element to attack Sabang Island and Koetaradja, another to land at Idi and secure the Langsa and Pangkalanbrandan oilfields, and the main element to land at Laboehanroekoe and move rapidly to occupy Medan.

On the afternoon of 6 March the units which were to proceed to Sabang and Koetaradja sortied from West Harbor (Keppel), Singapore on four transports escorted by the 3d Destroyer Squadron consisting of the 20th and 10th Destroyer Divisions and the 1st Mine Sweeper Division. (Map 1)

The force assigned for the invasion of the Idi area departed West Harbor on the morning of 9 March aboard two transports escorted by the Shumushu (DE) and the 2d Section of the 41st Mine Sweeper Division.

Also on 9 March at 1000 hours, the main elements of the Northern Sumatra Invasion Force with the mission of general support to the entire invasion departed Seletar, Singapore. This force consisting of the Chokai (Fleet Flag-Ship), the 7th Cruiser Division, the 11th and 12th Destroyer Divisions, and the seaplane tender Sagara Maru

1. Prior to the outbreak of war the 1st Southern Expeditionary Fleet was known as the Southern Expeditionary Fleet. It was redesignated the former on 3 January 1942 in order to avoid confusion with the 3d Southern Expeditionary Fleet which was activated the same day.


Chart 2




headed for the waters south of Great Nicobar Island.

The main body of the Imperial Guard Division on board eight transports left West Harbor on 10 March escorted by the Hatsutaka, the Nagoya Maru, No 7 Subchaser, and the 1st Section of the 44th Mine Sweeper Division.

These convoys proceeded under air cover provided by the 40th Naval Air Group from the Seletar Air Base, seaplanes from the tender Sagara Maru, and the Bihoro Naval Air Group from its base on Penang Island.

The main elements, charged with general support, arrived in the area northwest of Sabang Island on the evening of 11 March. Beginning at dawn on 12 March unopposed landings were made at Sabang, Koetaradja, Idi, and Laboehanroekoe.

By 15 March, all participating naval elements, with the exception of a small landing unit which remained to occupy Sabang, had returned to bases at Penang and Singapore and began preparations to support the impending Andaman Island and Burma invasions. (Monograph No 79)

Occupation of Christmas Island

Christmas Island, a tiny island situated approximately 200 miles south of Java was, despite its size, considered strategically important because its geographical position made it a key point for observation of sea traffic between India and Australia. And, with


plans already prepared for operations in the Indian Ocean, its occupation attained even greater significance.

Accordingly, upon completion of the occupation of Java, Imperial General Headquarters issued orders on 14 March directing the C in C, Combined Fleet to occupy the island. In turn, the 2d Southern expeditionary Fleet organized an occupation force under command of Rear Admiral Shoji Nishimura, commander of the 4th Destroyer Squadron, consisting of the light cruisers Naka and Natori, the 9th Destroyer Division (Asagumo, Natsugumo, Minegumo, Yamagumo), a detachment of twenty men from the 21st Special Base Force, who were to serve as an occupation garrison, and two transports for the carrying of phosphate, an abundant supply of which existed on the island.2 This force departed Bantam Bay, Java at 1900, 29 March and landed on Christmas Island at 0945 , 31 March. The landing was unopposed as the enemy garrison indicated its intention of surrendering by hoisting a white flag at the first sight of the invasion force. All elements, with the exception of the twenty-man garrison had returned to Bantam Bay by 3 April. (Map 2)

Invasion of Dutch New Guinea

On 5 March, Imperial General Headquarters by Navy Directive

2. The 2d Southern Expeditionary Fleet was activated on 10 March 1942 by redesignation of the 3d Fleet.




No 62 ordered the C in C, Combined Fleet, upon completion of the Java operation, to annihilate the remaining enemy force in the Dutch New Guinea area and to occupy strategic points of that territory. The objectives of the occupation were to survey the country for possible sites for air bases, anchorages, and oilfields, as well as secure a communication line to British New Guinea.

Plans evolved called for landings at Fakfak, Babo, Sorong, Manokwari, Momi, Seroei, Nabire, Sarmi, and Hollandia with the garrisoning of troops in the Fakfak and Manokwari areas. Also, it was planned that the force used would touch at Boela on Ceram Island to investigate the condition of an oilfield known to be there. (Map 3)

To carry out these operations the 2d Southern Expeditionary Fleet organized the Dutch New Guinea Invasion Force under command of Rear Admiral Ruitaro Fujita at Ambon on 15 March. (Chart 3)

As scheduled, a landing was made at Boela on 31 March. No resistance was encountered, but the destruction of the oilfield was so complete that no thought was given to its repair. Units of the invasion force landed and reconnoitered the immediate areas at Fakfak, Babo, and Sorong on 1, 2, and 4 April respectively without encountering any enemy forces. Approximately 150 enemy troops were reported at Manokwari, but by the time of the landing there on 12 April they had fled to the mountains. To counter any possible action by these troops, a detachment (192 men) of the 4th Guard




Chart 3

Naval Forces Employed for Dutch New Guinea Invasion

15 March 1942





Destroyer Escort






Seaplane Tender


Patrol Vessel


Heavy Cruiser


Reconnaissance Plane


Light Cruiser






Torpedo Bomber






Cargo Transport




Unit remained as a garrison. Landings and reconnaissances were made at Momi on the 15th, Seroei on the 16th, Nabire on the 17th, and Hollandia and Sarmi on the 20th, all without encountering any enemy troops. As a result of having met such a small number of the enemy, the force was dissolved at Manokwari on 21 April, with the participating units returning to Ambon.

Operations in the Lesser Sunda Islands

Final mop-up operations in the southwest Pacific called for the invasion of the Lesser Sunda Islands during the month of May. Elements of the 2d Southern Expeditionary Fleet used for this operation, under the command of Rear Admiral Kenzaburo Hara, Commander of the 16th Cruiser Division, included the cruiser Isuzu, minelayer Wakataka, the 1st Yokosuka Special Landing Unit (approximately of battalion strength), and an element from the Soerabaja Naval Base Force. Also participating, under Navy control was a unit of battalion strength from the 48th Division. After assembling at Soerabaja these units carried out landings on Lombok and Soembawa Islands on 9 May without encountering any enemy resistance. On 13, 14, 15, and 16 May respectively, Reo, Ende, Waingapoe and Larantoeka in the Flores Islands were occupied, all without opposition. The operation in the Lesser Sunda Islands was considered completed on 25 May and all participating elements with the exception of the 1st Yokosuka Special Landing Unit returned to their parent organizations.


This latter unit was broken up and elements assumed occupation and observation duties at Singaradja (Bali), Amdenan (Lombok), Bima (Soembawa), Waingapoe (Soemba), and Ende (Flores). (Map 4)

Areas of Responsibility

Southwest Pacific, May 1942

The conclusion of the Southern operation brought about a reorganization of the naval commands in the Southwest Pacific area to facilitate the transition from the offensive to the defensive, as well as to free combat elements for use in other areas. From the opening of hostilities to the successful completion of the Java occupation the naval forces operating in the Southwest Pacific were organized to conduct offensive operations. Following these victories the naval forces of this area were organized into a 1st, 2d, and 3d Southern Expeditionary Fleet with the mission of defense. Their organization consisted primarily of base forces to man and occupy strategic land installations and small patrol type vessels. To each fleet a cruiser was assigned as fleet flag-ship. This was done principally because of the communications facilities offered by a vessel of this type. Operational plans called for the integration into these skeletal fleets of combat elements from the Combined Fleet as needed.

Later, to further coordinate the naval defense of the Southwest Pacific, the Southwest Area Fleet was organized at Soerabaja, Java on 10 April 1942. This Fleet functioned as an intermediate head-




quarters between the Southern Expeditionary Fleets and Combined Fleet. To add readily available combat strength to this defensive arrangement the 13th, 22d and 32d Destroyer Divisions were assigned to the Area Fleet at the time of its activation. Also placed under its operational control were the 21st and 23d Air Flotillas of the 11th Air Fleet. The organization of the Southwest Area Fleet, as of 1 May 1942, and the division of its sectors of responsibility at that time are shown on Chart 4 and Map 5 respectively.


Chart 4

Organization of Naval Forces in the Southwest Area

(1 May 1942)

* Vice Admiral Takahashi concurrently held posts as C in C of the Southwest Area Fleet and 2d Southern Expeditionary Fleet.

** At this time these units were placed under operational control of the Area Fleet, but remained assigned to 11th Air Fleet. (Assigned Area Fleet as of 14 July 1942) Name of ships and bases indicate the flagship and station of the Headquarters.