Appendix J
Japanese Army-Navy Central Agreement on Southeast Area Operations, with Supplement, 15 March 1943
I. Operational Objectives
The objective of Southeast Area operations lies in securing or occupying the strategic areas in the theater and thus establishing a superior and impregnable strategic position.
II. Operational Strategy
A. Plan for directing the operations
The Army and Navy forces shall literally operate as one unit, and the primary operation of the two forces will be directed against New Guinea, in order to establish bases for further operations in this theater. In the meantime, defensive measures will be intensified in the Solomon Islands and Bismarck Archipelago to secure the important areas already occupied and to destroy the enemy whenever he attacks.
B. Operation in New Guinea
1. Secure the key points around Lae and Salamaua against enemy air and ground offensives. The Army and Navy units will employ all means at their command in securing the supply situation for the units in these areas, and will thus increase their combat potentiality.
2. Air operations will be intensified to destroy the enemy air strength. At the same time, primary importance in air operations will be attached to the sustained effort of cutting off enemy lines of communications and reinforcement extending to the eastern coast of New Guinea. Furthermore, nothing will be left to be desired in respect to the air cover that our own lines of communications and supply will receive.
3. To carry out the operations in New Guinea, the Army and Navy will cooperate in the effort of quickly completing and strengthening the group of necessary air, air defense and lines of communication, and supply bases in New Guinea and New Britain. Simultaneously, vitally necessary roads will be built, mostly by Army units, and special effort will be made in expediting the establishment of military supply dumps and thus completing the establishment of operational bases on New Guinea and on the western part of New Britain.
4. Along with the preparation and expansion of bases mentioned in the preceding paragraph, troops and equipment in the vicinity of Lae and Salamaua will be increased, in order to strengthen the security of these areas. Completion of other facilities will also be expedited in preparation for the forthcoming operation, which will be directed primarily against Port Moresby. Agreement on subsequent operations will be made separately.
C. Operations in the Solomon Area
1. The defense of the key points north of New Georgia Island and Isabel Island will be strengthened, and present conditions secured and expanded, so that enemy attacks can be repulsed at any time. Ground defense of this area will be shared by the Army and Navy as follows: Army—Northern portion of the Solomon Islands. Navy—Central portion of the Solomon Islands (New Georgia Island, Isabel Island, and adjacent islands) (some Army units will be placed under the Navy commander in accordance with agreement between the local Army and Navy commanders) .
2. The operations of the naval air forces and submarines will be directed to check enemy efforts to send reinforcements and supplies to the Guadalcanal area and to crush the enemy strength.
3. The Army and Navy units will cooperate in building the necessary roads on Bougainville Island as well as in establishing as quickly as possible a supply line extending to the Solomon Islands.
4. Operations in the Bismarck Archipelago
The Army and Navy will cooperate in strengthening the defenses on New Britain Island, especially the defenses in the western part of the island and around Surumi. Also, in order to maintain supply lines to New Guinea, they will be charged with the task of completing land and sea lines of communication bases.
III. Air Operations
A. Every effort will be made by both the Army and Navy to rapidly increase their air strength and maintain their combat strength. Thus an increase in air strength will be achieved as planned, and it will be fully prepared in bringing the overall operation to a successful end.
B. In directing air operations, emphasis will be placed on achieving cooperation between Army and Navy air strength.
C. Allocation of air responsibility between Army and Navy air units during the operation, especially up to around September 1943, will be as follows:
1. Army air units
a. Will cooperate with the Navy in protecting the lines of communications and supply in the New Guinea area and in the Bismarck Archipelago.
b. Will shut off enemy land transportation in the New Guinea area as well as support our ground and defense operations in the New Guinea area.
c. Will cooperate with the Navy in aerial supremacy battles in the New Guinea area.
d. Will cooperate with the Navy in cutting off the enemy’s sea lanes north of Buna.
2. Navy air units
a. Will intercept enemy surface transportation around New Guinea, as well as cooperate with the Army in aerial supremacy combat in the same area.
b. Will take part in the air operation in the Solomon area. Such an operation will consist of aerial supremacy combat, interception of enemy transportation, interception of enemy aircraft, ground support, and covering lines of communications and supply.
c. Will protect lines of communications and supply in Bismarck Archipelago area.
d. Will cooperate as much as possible, with the Army in protecting the lines of communications and supply in the New Guinea area.
c. In the defense of the Bismarck Archipelago, the Navy air units will be assigned the primary responsibility, and will receive the cooperation of the Army air units in the locality. Besides, the local air defense will be made by mutual cooperation of army and navy units in the locality.
3. Army and Navy air units will be called upon to supply the Army and Navy units in the New Guinea area via air whenever it is deemed necessary. ...
IV. Commanders, and Strength
Navy:
Commander—Commander in Chief of Combined Fleet
Unit—Main force of Combined Fleet
Army:
Commander—Commanding General of the 8th Area Army
Unit—Eighth Area Army
V. Chain of Command
Operations in this theater are basically conducted under cooperation between the Army and Navy. However, in the event that the Army and Navy are engaged in land operations in the same area at the same time, the senior commander of the area from among the Army and Navy will, as the occasion may demand, command the operation. ...
VIII. Transport and Escort
A. For the time being, Palau will be the relay point for forwarding of supplies (reinforcements) as well as for concentrating Army units in the Southeast Area. With use of its vessels the Navy will, when deemed necessary, cooperate as much as possible with the Army in transporting the foregoing Army units and supplies. In each instance, the Army Department and Navy Section of Imperial General Headquarters will, when the above cooperation is effected, determine the details.
B. Depending on operational conditions in the local operations, the Navy will assist the Army or will even carry the full burden of transporting materiel and Army units not covered in the preceding paragraph. Matters pertaining to such transportation will be studied and agreed upon by the Army and Navy commanders concerned.
C. The transport ships (including empty transports) returning from the Southeast Area will, insofar as is possible, return home directly from the point of departure. For the time being, however, Palau will be used as a relaying port, and the transports will, as much as possible, navigate in convoy formation. The local Army and Navy commanders concerned will determine the details on the navigation of the convoy.
D. The Navy will provide the necessary escort for convoys (including empty ships) on return voyages as well as for convoys transporting Army units and supply materiel to the fronts. In carrying out the escort procedure, the Army Department and the Navy Section of Imperial General Headquarters, or the Army and Navy commanders concerned will, as specified in the preceding paragraphs, determine the details on the convoy escort. .. .
Supplement
The Agreement Between the Army and Navy Commander
1. Assignment of air bases to be used by Army and Navy.
a. Primarily Army:.
Rabaul (South) Wake Island, Lorengau, Finschhafen
b. Primarily Navy:
Rabaul (East) Kavieng, Surumi
c. Jointly used by Army and Navy:
Rabaul (West, Bamo, Tuluvu, Lae, Madang, Wewak, Babo, Hollandia
2. The local Army and Navy commanders will decide as to which airfield or airfiields will be designated for joint use in the Lae, Madang and Wewak airfield group, and as to which branch of service will use the new airfields, pending construction.
3. In addition, the Army will use Palau as a shelter airfield for one bomber regiment.
4. Army will, until the air bases necessary for its own use are constructed and for operational and supply reasons, provide necessary ground duty units and facilities for air security to the following Navy air bases: Mindanao, Manado, Ambon, Namlea, Boela, Palau, Kendari and Makassar.
5. The Army and Navy will, according to operational circumstances, mutually facilitate and utilize the respective air bases and will mutually render assistance in supply and in air base maintenance.
6. Summary
Bringing the operations in the Southeast Area, especially in New Guinea, to a successful end is a matter of vital importance to the national defense of our Imperial homeland. Therefore, there are ample reasons to fear that poor planning or execution of the operation would lead to grave consequences. Furthermore, in order to maintain the impregnable strategical position of the Southeast Area at large, it is absolutely a minimum prerequisite to securely hold the present positions in New Guinea, Solomon Island and Bismarck Archipelago Areas. Serious failure in any of these areas would jeopardize the entire Southern Region.
Arriving at the foregoing estimation of the situation, the Army Department and the Navy Section of Imperial General Headquarters have agreed to exert all their efforts and bring the Southeast Area Operation to a successful end at all costs, under the plan singularly followed by both the Army Department and Navy Section of Imperial General Headquarters and the frontline echelons. It is based upon the joint strategical plan sanctioned by the Emperor on March 5th and on the strategical study conducted in the presence of His Majesty.
7. These are the steps to be taken as immediate measures by the Army Department and Navy Section of Imperial General Headquarters.
a. Strengthening of respective Air Arms.
In the Southeast Area both branches of service will hastily increase their air strength or bring up the air units presently there to full strength, designate their areas of responsibility and increase and strengthen their air bases in those areas, and thus complete their preparations for air operations.
b. Supply, especially to these units in eastern New Guinea, must be carried out under a joint Army-Navy effort and with all available means at their command. To accomplish this objective, the following measures will be taken without delay.
(1) Both services will quickly increase the number of barges and other surface craft in the Southeast Area.
(2) Under joint Army-Navy effort, the facilities of the line of communications of small surface craft will be completed, and the transportation of supplies by small surface craft will be expedited. Furthermore, the Navy will, with a group of Naval vessels, enforce emergency transportation of supplies. The Army will exert every effort in maintaining the land lines of communications. Also, supply by air will be stepped up.
(3) However, in the event that it becomes impossible to cope with the situation with the aforementioned measures, which are to be enforced with every means available, the Navy will carry out the task of supply with every available means at its command.
c. The Army will, without loss of time, send new contingents of air defense troops required in the establishment of air bases and strengthen the defensive facilities in the New Guinea area. Furthermore, the Army, in addition to the foregoing assignments covered in the earlier plan, will put the Army transports at its disposal to maximum use and transport the newly-reinforced units to the Southeast Area. The Navy will assist in the transporting as much as possible.
8. Since how to supply our troops stationed in the zone within the radius of enemy aircraft has a decisive effect on the future course of the war, concrete plans will be made quickly and various means to insure its execution will be expedited, together with organizing the necessary materiel.
9. The Army Department and Navy Section of Imperial General Headquarters will formulate a joint concrete plan to direct their operations.
10. The Army-Navy Central Agreement on the South Pacific Ocean Area Operation, which is in effect at present, will be revised on the basis of the foregoing plans.
11. The Army Department and Navy Section of Imperial General Headquarters will direct their respective front line echelons in accordance with the preceding plan formulated at Imperial General Headquarters and will strive to achieve complete harmony and cooperation in directing operations. As a most practicable measure to realize this central plan, the Army Department and the Navy Section will simultaneously call their respective chiefs of staff of the local Army and Fleet back to Tokyo toward the end of March and issue the necessary instructions on the foregoing matters.