J. C. S. Files

Plan Prepared by the United States Joint Staff Planners 1

secret

Attachment to C.C.S. 220

Strategic Plan for the Defeat of Japan

1. A brief discussion of a strategic plan for the defeat of Japan is contained in Enclosure “A”.

2. The plan is based on the following overall strategic concept for the prosecution of the war. [Page 290]

a.
In cooperation with Russia and other Allies to force an unconditional surrender of the Axis in Europe.
b.
Simultaneously, in cooperation with other Pacific Powers concerned, to maintain and extend unremitting pressure against Japan with the purpose of continually reducing her Military power and attaining positions from which her ultimate unconditional surrender can be forced.
c.
Upon the defeat of the Axis in Europe, in cooperation with other Pacific Powers and, if possible, with Russia, to direct the full resources of the United States and Great Britain to force the unconditional surrender of Japan. If, however, conditions develop which indicate that the war as a whole can be brought more quickly to a successful conclusion by the earlier mounting of a major offensive against Japan, the strategical concept set forth herein may be reversed.

3. In view of the long period covered and the inevitable changes in conditions that cannot be foreseen, it is not practicable to divide the plan into definitely coordinated phases. With this reservation in regard to timing and coordination, the plan is expressed as follows:

Phase I

a.
Continue and Augment Existing Undertakings in and From China.
Chinese Forces assisted by U. S. Forces.
b.
Recapture Burma.
British Forces assisted by U. S. and Chinese Forces.
c.
Open a Line of Communications to the Celebes Sea.
United States Forces.

Phase II

a.
Operations To Open the Strait of Malacca and To Compel Wide Dispersion of Enemy Forces.
British Forces.
b.
Recapture the Philippines.
United States Forces.
c.
Prepare To Capture Hong Kong.
Chinese Forces.

Phase III

a.
Continue Operations To Open the Strait of Malacca and To Compel Wide Dispersion of Enemy Forces.
British Forces.
b.
Secure Control of the Northern Part of the South China Sea, and Assist in the Capture of Hong Kong.
United States Forces.
c.
Capture Hong Kong.
Chinese Forces.

Phase IV

  • Establish Air Bases in Japanese Occupied China From Which To Launch an Overwhelming Bombing Offensive Against Japan.
  • Chinese Forces, assisted by British and U. S. Forces.
[Page 291]

Phase V

  • Conduct an Overwhelming Air Offensive Against Japan.
  • U. S. Forces, assisted by British and Chinese Forces.

Phase VI

  • Invade Japan.
  • U. S. Forces, assisted by British and Chinese Forces.

Enclosure “A”

Strategic Plan for the Defeat of Japan

4.2 Objective of the Plan

The United Nations war objective is the unconditional surrender of the Axis Powers. The accomplishment of this objective may require the invasion of Japan.

5. Most Probable Japanese Courses of Action

Japan’s most probable courses of action are to direct her major effort toward securing and exploiting the territory she controls, and eliminating China from the war.

6. The Invasion of Japan

Since the invasion of Japan is a vast undertaking, it should not be attempted until Japanese power and will to resist have been so reduced that favorable conditions for invasion obtain. Under these conditions the invasion of Japan is considered feasible.

It is probable that the reduction of Japan’s power and will to resist may only be accomplished by a sustained, systematic, and large-scale air offensive against Japan itself.

7. An Overwhelming Air Offensive Against Japan

An air offensive on the required scale can only be conducted from bases in China.

8. Recapture Burma

The attainment of bases in China for the air offensive against Japan is dependent on the continuation of China in the war, and on the establishment of adequate supply routes, not only to maintain China, but also to maintain United Nations forces which are to operate in and from China. The recapture of Burma is a prerequisite to the attainment of adequate bases in China. The capacity of the Burma Road supplemented by the air route from India is inadequate to support the air and ground forces required to implement an air offensive on the required scale. The seizure of a port in China to augment the supply routes through Burma is essential.

[Page 292]

9. The Seizure of a Port in China

Hong Kong is the most suitable port which may be seized initially. Its seizure requires an offensive from the interior of China by forces supported through Burma, and, probably by supplementary amphibious operations. Control of the South China Sea by the United Nations will be necessary to prevent Japan from successfully opposing these measures.

10. A Line of Communications to Hong Kong

The most feasible sea route from the United States to Hong Kong is through the Celebes and Sulu Seas; that from the United Kingdom is through the Strait of Malacca. The establishment of these routes will require the neutralization of Japanese bases in the northern East Indies, the Philippines, Formosa, and on the Asiatic mainland south of Hong Kong. Control of these areas will prevent Japan from suporting her forces in the Netherlands East Indies and will deny her the economic advantages she receives from that area. Operations to open a line of communications to Hong Kong and to control the South China Sea are considered feasible.

11. A Line of Communications From Hawaii to the Celebes Sea

This line of communications to the Celebes Sea will be established by advancing in the Central and Southwest Pacific areas with a view to shortening the sea route, providing for its security, and denying to the enemy bases and means by which he may interfere with the line of communications.

12. A Line of Communications Through the Strait of Malacca

Although the supply of forces in China will come mainly from the United States, operations to open the Strait of Malacca, after the reconquest of Burma, are a vital part of the plan. The enemy must be continuously compelled to disperse his forces throughout the Pacific and Asiatic areas thus exposing them to attrition on an additional front in Southeastern Asia. This area is one of British strategic responsibility, and is a suitable and feasible undertaking for British Commonwealth Forces.

13. Control of the Seas

Since control of the seas in the western Pacific by the United Nations may force the unconditional surrender of Japan before invasion and even before Japan is subjected to an intensive air offensive, every means to gain this control will be undertaken by the United States. The establishment of the line of communications to the Celebes Sea will be used as the vehicle to gain this end. The selection of intermediate objectives which will compel the enemy to expose his naval forces will be the greatest single factor in determining the enemy positions to be seized.

[Page 293]

Attrition of enemy shipping, air, and naval resources will be a continuing objective. Raids on Japanese lines of communication, and carrier-based air raids on Japanese positions extending to Japan itself, will be implemented as our naval strength increases.

  1. Circulated to the Combined Chiefs of Staff on May 19, 1943, under cover of a memorandum by the United States Joint Chiefs of Staff reading as follows: “The attached strategic plan, prepared by the United States Joint Staff Planners, meets with the approval of the United States Chiefs of Staff and is submitted to the Combined Chiefs of Staff for consideration.” This plan was discussed by the Combined Chiefs of Staff at their meeting on the morning of May 20, 1943, and it was accepted as a basis for a combined study and elaboration for future plans; see ante, p. 126.
  2. Enclosure “A” begins with paragraph 4.