Foreign Relations of the United States: Diplomatic Papers, The Conferences at Cairo and Tehran, 1943

J. C. S. Files

Report by the Combined Staff Planners²

secret
C. C. S. 417

[Cairo,] 2 December 1943.

Over-All Plan for the Defeat of Japan

problem

1. To prepare an over-all plan for the defeat of Japan.

assumptions

2. Our studies of this subject have taken account of:

a. The possibility that invasion of the principal Japanese islands may not be necessary and the defeat of Japan may be accomplished by sea and air blockade and intensive air bombardment from progressively advanced bases. The plan must, however, be capable of expansion to meet the contingency of invasion.

b. The possibility that Germany may be defeated as early as the spring of 1944.

c. The possibility that the U. S. S. R. may enter the war against Japan early after the defeat of Germany, and our plan proposes that all possible preparations should be made to take advantage of such a development. Further progress is dependent upon staff conversations with the Soviets.

d. The possibility that a full campaign in Burma may have to be carried out following on the Tarzan operation.³

over-all objective

3. To obtain objectives from which we can conduct intensive air bombardment and establish a sea and air blockade against Japan, and from which to invade Japan proper if this should prove to be necessary.

general concept

4. The main effort against Japan should be made in the Pacific.

concept within the pacific

5. The advance along the New Guinea-N. E. I.-Philippine axis will proceed concurrently with operations for the capture of the Mandated Islands. These two series of operations will be mutually supporting. United Nations naval forces can be deployed to support successive operations along each axis, and to prevent interference by hostile surface units with simultaneous operations in the two areas. Transfer of forces and resources from one area to the other is contemplated. When conflicts in timing and allocation of means exist, due weight should be accorded to the fact that operations in the Central Pacific promise at this time a more rapid advance toward Japan and her vital lines of communication; the earlier acquisition of strategic air bases closer to the Japanese homeland; and, of greatest importance, are more likely to precipitate a decisive engagement with the Japanese Fleet.

The aim should be to advance along the New Guinea-N. E. I.-Philippine axis and to complete the capture of the Mandated Islands in time to launch a major assault in the Formosa-Luzon-China area in the spring of 1945 (i. e., before the onset of the typhoon season), from a distant base.

concept within other areas

6. Operations in the North Pacific, the South Pacific, China and the Southeast Asia Theater should be conducted in support of the main operations in the Central and Southwest Pacific. In the event of the U. S. S. E. entering the war, operations in the North Pacific may assume far greater importance and may involve a major redeployment of forces.

general conduct of operations

7. The conduct of operations should be designed to:

a. Destroy the Japanese Fleet at an early date.

b. Secure the maximum attrition of enemy air forces.

c. Intensify air, submarine and mining operations against enemy shipping and lines of communication.

d. Enable us to launch shore-based and carrier-borne air attack on Japan.

e. Keep China in the war.

f. Insure that the sequence of operations remains flexible and that preparations are made to take all manner of short cuts made possible by developments in the situation.

g. Take advantage of the earliest practicable reorientation of forces from the European Theater.

specific operations in 1944

8. For operations planned for 1944, see schedule in C. C. S. 397, Specific Operations for the Defeat of Japan, 1944 (To be revised) .⁴ These operations are in accordance with the over-all concept. In brief they contemplate:

Central Pacific

a. Capture of the Mandated Islands and conduct of V. L. R. strategic bombing of Japan proper from the Marianas (Guam, Tinian and Saipan).

Southwest Pacific

b. Continuing the advance along the New Guinea-N. E. I.-Philip-pine axis. Intensification of air bombardment of targets in the N. E. I.-Philippine area.

North Pacific

c. Preparations to conduct very long range strategic bombing against the Kuriles and Northern Japan. (Preparations for the possible entry of the U. S. S. R. into the war are discussed in Annex I.)

Southeast Asia Theater

d. Operations for the capture of Upper Burma in the spring of 1944 in order to improve the air route and establish overland communications with China, and an amphibious operation at approximately the same time. Continuance of operations during the autumn of 1944 within the limits of the forces available (see paragraph 14) to extend the position held in Upper Burma.

e. Should the means be available, additional ground, sea and air offensive operations, including carrier-borne raids, with the object of maintaining pressure on the enemy, forcing dispersion of his forces, and attaining the maximum attrition practicable on his air and naval forces and shipping.

China Area

f. Conducting V. L. E. air operations from the Chengtu area in China against vital targets in the Japanese inner zone.

g. Building up the U. S. Air Forces in China and the Chinese Army and air force with the object of intensifying land and air operations in and from China.

disposition of forces

Naval Forces

9. Considering the British Naval forces shown below, we believe the combined naval forces will be adequate to conduct the operations envisaged for the defeat of Japan. We show in Annex ii⁵ the estimated dispositions of British Naval forces in the Indian Ocean and the Pacific after the completion of operation Buccaneer, and the subsequent build-up of British Naval forces in the Pacific during 1944 and early 1945.

10. This allocation provides for sufficient forces in the Indian Ocean to maintain our communications with the Andamans, to act as a deterrent against any attempt to recapture them by the Japanese and to carry out operations, raids and threats against Japanese possessions in S. E. Asia. All other available units, to the extent that they can be supported and profitably employed, will be concentrated for the main effort in the Pacific.

11. Though full details have not yet been worked out, we consider that the British naval forces shown can be supported logistically and should in general operate from advanced bases in the Bismarck and Solomons area so that they may either cover the operations along the New Guinea-N. E. I.-Philippines axis, or cooperate with the U. S. Fleet in the Central Pacific.

12. Logistic preparations should be made by the British for the increased British naval forces expected to become available for the long distance assault contemplated in the spring of 1945. Manpower limitations will probably prevent any new bases being manned by the British until after the defeat of Germany.

13. Our studies have reemphasized the importance of the provision of aircraft carriers of all sorts for our future operations against Japan.

Land Forces

14. Present plans contemplate the timely deployment in the Pacific of about 40 U. S. divisions and supporting troops. British/Indian land forces, which can be made available to Southeast Asia command up to the end of 1944 are likely to be fully committed in carrying out the operations recommended for the season 1943/44, and subsequently extending the area of occupation in Burma and in carrying out additional operations against the enemy. This concept is subject to alteration in the light of the progress of the 1943/44 operations and of detailed examination of the forces which will be required for 1944/45, but included in the forces retained in the theater there should be at least one amphibious division.

15. After the defeat of Germany the number of additional British divisions from the European Theater and the dates by which they can be made available for the war against Japan cannot yet be assessed, but it is estimated that some nine months will be required for the necessary reorganization, passage and training. Additional British forces may prove essential for Burma. In the Pacific, the target should be to provide four British divisions based on Australia for service in that theater as early as possible after the defeat of Germany. At least two of these divisions should be amphibiously trained.

16. After providing for paragraph 15 above, additional British forces becoming available will probably be best placed in reserve at the disposal of Southeast Asia, ready for additional offensive operations in that area.

17. Australian and New Zealand forces should continue to be employed in Pacific operations. The employment of Canadian forces should be discussed with the Canadian Government.

18. We believe that the combined land forces to be made available as outlined in paragraphs 14, 15, 16 and 17 above will be adequate to conduct the operations envisaged for the defeat of Japan.

Assault Shipping and Landing Graft

19. Present plans contemplate an eventual U. S. assault lift of 12 divisions in the Pacific. The British should maintain in the Southeast Asia Theater an assault lift for at least one division. As soon as the war with Germany is over the British should aim to provide in the Southwest Pacific as large an assault lift as possible (probably between two and three divisions simultaneously).

Air Forces

20. British and U. S. air forces are sufficient for plans at present contemplated although if the U. S. S. R. enters the war the demand on our resources for the establishment of a bomber force in the Maritime Provinces may conflict with the development of our air effort against Japan through China.

The large air forces which will be available when Germany is defeated must be redeployed against Japan as quickly as possible. The general principles which we consider should govern this redeployment are in Annex III. Immediate examinations of the problems involved in this redeployment of British and U. S. air forces should be made. Studies are now under way to determine the best employment of the B–29 aircraft against Japan.

Appendix “A” to Annex III⁶ shows the U. S. and British air forces which may be available for deployment against Japan after the defeat of Germany.

preparation of bases in india

21. The preparation of the bases in India required for approved operations in the Southeast Asia and China Theater should continue in consonance with provisions of paragraphs 4, 5 and 6.

recommendations

22. It is recommended that the Combined Chiefs of Staff:

a. Approve the over-all plan for the defeat of Japan and direct that the necessary preparations be initiated.⁷

b. Approve the specific operations set out in C. C. S. 397, Specific Operations for the Defeat of Japan, 1944. (To be revised) .⁸

Annex I

Note on Preparations That Should Be Made for Possible Russian Entry Into the War

1. We should urge the U. S. S. R. to come in as early as possible; ask them to tell us when they propose to come in; what they propose to do when they come in; and what they want us to do to help.

2. Meanwhile, in so far as they do not conflict with the operations in the Central and Southwest Pacific, preparations should be made by the spring or early summer of 1944 so that we can assist her:—

a. By building up supplies by trans-Pacific shipment, sea and air.

b. By insuring that her defenses and means in Kamchatka are adequate. If she wants our forces there we should be prepared to move them in, especially air.

c. By furnishing aircraft and air units released from the European front, both from the East and the West.

3. If and when conversations with the Soviets can be arranged, plans should also be made for operations:—

a. To enter and develop bases in Kamchatka and the Maritime Provinces.

b. To seize and hold the Northern Kuriles and to open a sea route to the Maritime Provinces.

c. To supply and operate air forces from Siberian bases.

4. We must constantly review the situation so as to be ready to adjust our operations elsewhere when the U. S. S. R. come into the war.

Annex III

Air Forces

availability of air forces

1. Appendix “A”⁹ shows the British and U. S. air forces that may become available for the war against Japan on the alternative assumptions that Germany is defeated in March or October 1944.

These large air forces must be deployed against Japan as quickly as possible.

redeployment of air forces

Pacific

2. We should speedily increase our air forces in the Central, Southwest and North Pacific. The air forces in the Central Pacific will be U. S.; those in the Southwest and possibly in the North Pacific will be both British and U. S.

Southeast Asia

3. In Southeast Asia we must deploy sufficient air forces to insure the security of the area, protect our sea communications and to meet the requirements of operations. These will be predominantly British.

U. S. S. R. and China

4. A study is now being made to determine the best employment of B–29 aircraft in the war against Japan.

In so far as operations from China are concerned, we have under consideration the Drake Plan for V. L. E. bombing from the Kweilin area and a plan for V. L. E. bombing from the Chengtu area (plan Matterhorn) . We recommend approval of the Matterhorn plan on the understanding that it is not permitted to interfere materially with other approved operations.

The preparations now underway for the Chengtu operations are also preliminary for the Drake plan.

Further study of the Drake plan is required, especially with regard to the logistic features.

5. With respect to whether we carry out Drake operation from China or V. L. E. bombing from the U. S. S. R., we consider that:

a. If the U. S. S. E. enters the war, grants us facilities and we are able to establish and maintain a bomber force in the Maritime Provinces, the establishment and the operation of such force should have priority over the Drake plan.

6. If the U. S. S. E. enters the war but it does not prove feasible to establish and maintain a bomber force in the Maritime Provinces, we should proceed with the Drake plan. In this case the requirement in Chinese divisions for the defense of the forward area should be considerably reduced below the figure of 50 stipulated by General Stilwell. If 20 divisions only were required we might start bombing Japan by autumn 1945.

c. If the U. S. S. E. does not enter the war, we should proceed with the Drake plan. If the full figure of 50 divisions is necessary, bombing could not start before the end of 1946.

examinations required

6. We do not consider that at this stage we can go further than the above. We recommend, however, that the following examinations should be carried out as a matter of urgency:

a. A proposed redeployment of the British and the U. S. air forces in the light of the above principles, after the defeat of Germany, setting out the types and strengths required in the various areas.

b. Drake Plan

(1) To be examined by S. A. C. S. E. A.¹⁰ and Commander in Chief, India.¹¹

(2) A study as to the extent to which Lancaster/Halifax aircraft could take the place of the B–24 on which our staff study has been based.

c. It is most desirable to examine as early as practicable with the Soviets the problems involved in establishing and maintaining a U. S. British air force in the Maritime Provinces of the U. S. S. E., leading to conclusions as to the size of force that may be achieved and the effort required to maintain it by sea, land and air routes. This will depend upon staff conversations with the Soviets.

Appendix “b” to Annex iii

“Drake” Plan

1. The plan is to bomb Japan with B–29 aircraft supplied through India and operating through forward airfields in the Kweilin area of China. This forward area would be protected by U. S. equipped Chinese divisions and the augmented 14th Air Force.

2. Twenty-seven airfields would be constructed (or converted) in Bengal. These would be supplied with gasoline by pipelines direct from the port. This would necessitate considerable expansion of the port facilities of Calcutta (both for dry stores and for gasoline) and communications in India, including the Bengal/Assam L. of C. In addition, the plan would require the construction of the Ledo-Pao-shan-Kunming road and the projected pipelines from India to China.

3. Simultaneously with the above, fifteen airfields would be constructed in the Kunming area, using Chinese labor and local resources.

4. On the completion of these projects supplies would be moved from India into China by approximately 2,000 transport aircraft (our plan is based on B–24’s), the Ledo–Kunming road and the oil pipelines. These supplies would equip and maintain Chinese forces and the augmented 14th Air Force. As soon as sufficient forces have been built up to protect the Kweilin area, airfields would be constructed there for use by the B–29 aircraft.

5. General Stilwell has stipulated that he would require 50 U. S. equipped and trained Chinese divisions before he could secure the Kweilin area sufficiently to allow airfield construction to be started. On this basis bombing could not start before the autumn of 1946. If a lesser force were acceptable, bombing could start correspondingly earlier (e. g., if 20 divisions would suffice, bombing might start in autumn 1945). The above dates assume the defeat of Germany by 1 October 1944.

6. The maximum B–29 force which we could operate would be eight groups (224 aircraft).

7. The plan allows for the Chengtu project, preparations for which have already been ordered.

8. The plan would be dependent upon the following assumptions:

a. That operations in North Burma in 1943/44 enable construction of the Ledo–Paoshan–Kunming Road and pipelines to be completed by 1 January 1945.

b. That sufficient airfield sites (27) in Bengal and port and communication facilities can be made available.

c. That the Bengal/Assam L. of C. is expanded as directed at Quadrant.¹²

d. That we can construct suitable airfields (15) in China with local labor and materials.

e. That during 1944, 7,000 tons a month (including 5,000 already allotted to the 14th Air Force) are made available from the capacity of the existing A. T. C. route to China.

f. That the necessary U. S. personnel and equipment are made available by the dates required.

2. Prepared for the Combined Chiefs of Staff pursuant to their request of November 25, 1943; see ante, p. 349.
3. This paragraph was added to C. C. S. 417 by the Combined Chiefs of Staff at their meeting of December 4, 1943, 2:30 p.m.; see ante, p. 688.
4. C. C. S. 397 (Revised) is printed post, p. 779.
5. Not printed herein.
6. Appendix “A” is not printed herein.
7. For the action of the Combined Chiefs of Staff on this recommendation, see ante, p. 736.
8. C. C. S. 397 (Revised) is printed post, p. 779. For the action of the Combined Chiefs of Staff with reference to that paper, see ante, p. 736.
9. Not printed herein.
10. Admiral Mountbatten.
11. General Auchinleck.
12. The records of the First Quebec (Quadrant) Conference, August 1943, are scheduled to be published subsequently in another volume of the Foreign Relations series.