The Combined Staff Planners to the Combined Chiefs of Staff
Québec, 18 August 1943.
Secret
Enclosure to CCS 313
Memorandum
Subject: Appreciation and Plan for the Defeat of Japan (CPS 83)
In their 90th Meeting on 20 May 1943, the Combined Chiefs of Staff:
…directed the Combined Staff Planners to initiate a study and prepare for consideration by the Combined Chiefs of Staff an appreciation leading up to an outline plan for the defeat of Japan, including an estimate of the forces required for its implementation.
In their 102nd Meeting on 16 July 1943, the Combined Chiefs of Staff directed the Combined Staff Planners to place an appreciation and plan for the war against Japan before the Combined Chiefs of Staff during QUADRANT.
Combined planning teams, working in London in June and in Washington in July, completed CPS 83 on 8 August with the exception of certain Tables of Forces which are under preparation and should be completed prior to the end of QUADRANT. A summary of CPS 83 is attached.
On the basis of the premises adopted, the Combined Staff Planners consider that the measures set forth as being necessary for the defeat of Japan, namely, the retention of China as an effective ally, the destruction of Japanese sea and air forces, the blockade of Japan, and the large-scale bombing of the Japanese homeland as a preliminary to the possible invasion of Japan, are sound.
The general lines of advance – through the Central and Southwest Pacific, and possibly in the Northwest Pacific by United States’ forces; and through the Straits of Malacca and China Sea by British forces, with the development of a line of supplies to China through Burma, are concurred in.
The dates on which operations are to be undertaken, with the consequent prolonged duration, envisages, as set forth by the Planning Team, the least favorable conditions to be anticipated. The Planning Teams state that conditions less unfavorable will permit the expediting of the contemplated operations.
Even on this conditional basis the Combined Staff Planners consider that the plan contemplates a war in the Pacific so prolonged as to be unacceptable to the United Nations. They feel that the situation existing at this time is that the Japanese have won the war and that operations which do not contemplate the complete nullification of Japanese gains before 1947 will produce the serious hazard that the war against Japan will not, in fact, be won by the United Nations.
The United Nations’ overall objective, as approved in CCS 242/6 during the TRIDENT Conference, states:
The overall objective of the United Nations is, in conjunction with Russia and other Allies, to bring about at the earliest possible date the unconditional surrender of the Axis Powers.
The Combined Staff Planners feel that the conduct of the war to bring about the defeat of Japan must be in consonance with the overall objective, as well as with the over-all strategic concept for the prosecution of the war against Japan, which reads (CCS 242/6, Paragraphs 1, 2 and 3):
In cooperation with Russia and other allies to bring about by the earliest possible date the unconditional surrender of the Axis in Europe.
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 surrender can be forced. The effect of any such extension on the overall objective to be given consideration by the Combined Chiefs of Staff before action is taken.
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 bring about at the earliest possible date the unconditional surrender of Japan.
At the present time a great preponderance of the United Nations Forces is deployed against the Axis Powers in Europe. At the time of the defeat of Germany large forces will become available for redeployment against Japan. This redeployment will require a long period of time. During this period the will to prosecute the war to the defeat of Japan will suffer from the stultifying effect caused by long delays in the increase of offensive action in the Pacific and Far East.
The Combined Staff Planners feel, therefore, that, if we are to comply with the approved overall objective and strategic concept and are to ensure the complete defeat of Japan, we must contemplate the start of the reorientation of forces from four to six months in advance of the prospective date of the defeat of Germany, adjusting the tempo and scale of the reorientation to the progress of the war in Europe, as determined by the Combined Chiefs of Staff from time to time.
The U.S. Planners feel that our plans and preparations should contemplate the defeat of Japan not later than 12 months after the defeat of Germany. This timing should itself now be established as a more or less controlling objective with which our efforts, measures, and courses of action should conform. If, in the future, the measures set forth in the proposed plan do not prospectively provide for this desired rate of progress of the war, other measures should be sought – as, for instance, inducing Russia to enter the war. The British Planners, however, while fully conscious of the need to shorten the war against Japan and to take all possible measures so to shorten it, cannot accept such a target date. In their opinion such acceptance would necessitate an entirely new concept of operations involving an assault on the Japanese homeland without the preparatory bombing from bases in China and/or Formosa which they believe will be required. This course, though worthy of consideration nearer the time, is insufficiently certain to provide a basis for long term planning.
The chief value of an overall plan of this kind is the guidance of action now and in the immediate future. Operations now underway in the North, Central, South, and Southwest Pacific, as well as those Pacific operations set forth in CCS 301 – Specific Operations in the Pacific and Far East, 1943-1944 – are in conformity with the plan. Operations for the seizure of Burma are in conformity with the plan, but the date that they should be undertaken is in dispute.
The U.S. Planners consider that the Southwest Pacific operations, through New Guinea, and to the Northwest of New Guinea, provide for a line of advance which at this time must be considered concurrent and coordinated with the advance in the Central Pacific and in this respect do not agree with the plan that these operations should he considered subsidiary in character.
The British Planners however consider that operations in New Guinea will be slow and very expensive in resources. They therefore support the view set out in the summary that when we turn to our main Pacific effort, through the Marshalls and Carolines, operations in New Guinea should become subsidiary and should only be pursued in so far as they are necessary for the success of our main effort.
The U.S. Planners assume that the operations in North Burma, as approved at the TRIDENT Conference – advance from Ledo and Imphal, and increase of supplies by air to China, and the Akyab and Ramree operations – will be firmly carried out in 1943-1944. Beyond these operations the plan submitted by the British Members does not contemplate offensive operations from the West (other than further operations in North Burma) until March, 1945. In other words, during the period March, 1944, to March, 1945, the efforts from the West 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” would be only those possible to the forces deployed in North Burma. The U.S. Planners feel that a more extensive contribution to the war effort is necessary along this line of advance during this period. They feel that the support rendered in 1944, even though smaller than could be afforded in 1945, will give better and more needed support to the Pacific Theater.
The U.S. Planners consider that Course B, the capture of South Burma, beginning in November, 1944, should be carried out. This operation is regarded as necessary not only for the improved line of supplies to China through Rangoon, but as a preliminary to the further movement of the advance from the West through the Strait of Malacca. In this they are in disagreement with the British Planners who concur with Course C, the attack against Singapore to bypass South Burma, and to be inaugurated in March, 1945.
The British Planners feel that the question of whether or not China remains in the war will not be decided by the choice between Course B (the prior capture of Burma) and Course C (the prior capture of Singapore) since China’s darkest hours will be in the early half of 1944, before Germany is defeated. Thereafter, the obvious weight of the United Nations offensive against Japan in general and the prospect of an early opening of the sea route in particular will do more to sustain morale than the arrival of limited additional material through Burma, always provided supply by the air route continues at the maximum.
The British Planners feel strongly that the recapture of Southern Burma and Rangoon would be a small strategic gain for the expenditure of great effort. At best it would:
a. Produce limited pressure on Japanese land and air forces for two dry seasons with little attrition during the intervening wet seasons.
b. Open the Burma Road. As this cannot in any case be in full operation before some time in 1946, whether we go for Rangoon or Singapore first, the results are long term. In the unlikely event of the Japanese in the meantime occupying Kunming, all our efforts in Burma would be nullified.
On the other hand, the British Planners feel that the recapture of Singapore before Rangoon is a full and correct application of sea and air power. It will electrify the Eastern world and have an immense psychological effect on the Japanese. It will threaten the Japanese communications to Thailand and so to Burma, enable direct attack to be brought to bear on the Dutch oilfields, and in fact flank and undermine the whole Japanese defense structure in Southeast Asia. It provides a base for the great naval and air forces available for deployment against Japan from the West. Above all, it provides for an advance complementary to that being undertaken by the USA from the East, and converging upon the same objectives, i.e., the capture of Hong Kong or Formosa and the control of the South China Sea. It thus accelerates the opening of a sea supply route to China. Operations against Singapore will, moreover, provoke intense Japanese reaction to preserve the material gains of the Japanese Empire in the West as opposed to its strategical position and gains in the East, thereby relieving Japanese pressure on China and stretching Japanese ability to resist the Eastern advance possibly to the limit.
Recommendations
To summarize, it is recommended that the Combined Chiefs of Staff should take the following action:
| Recommendations By U.S. Planners | Recommendations By British Planners |
|---|---|
| (a) Approve the general objectives and the general lines of advance set forth in the plan, as a basis for planning and preparation. | (a) Agreed. |
| (b) Disapprove, as unacceptable those aspects of the plan which contemplate a prolonged war lasting into 1947 or 1948. | (b) Agreed. |
| (c) Direct that plans and preparations for the defeat of Japan shall have as their objective the accomplishment of this defeat not later than 12 months after the defeat of Germany. | (c) Direct that intensified study of ways and means for shortening the war should be undertaken at every stage; and that theater commanders should be so instructed. |
| (d) Approve, in principle, the inauguration of reorientation of forces from the European Theater to the Pacific and Far East Theaters from four to six months in advance of the prospective date of the defeat of Germany, the scope and timing of reorientation to be adjusted to the requirements of the European Theater, as determined by the Combined Chiefs of Staff from time to time. | (d) Agreed. |
| (e) Recognize that the deployment of forces and the operations to be undertaken in the war against Japan must be in accord with the overall objective and strategic concept defined in CCS 242/6, Sections I and II. | (e) Agreed. |
| (f) Reaffirm the TRIDENT decision that approved operations in North Burma and against Akyab and Ramree will be executed during the coming dry season. | (f) The British Planners consider that the form of this decision must await the outcome of discussion on CCS 301. |
| (g) Reaffirm the TRIDENT decision to undertake such measures as may be necessary and practicable in order to aid the war effort of China as an effective ally and as a base for operations against Japan. | (g) Agreed. |
| (h) Direct the maximum possible expansion of the air supply route into China. | (h) Agreed. |
| (i) Approve the Pacific operations as accepted in the final version of CCS 301. | (i) Agreed. |
| (j) Make a decision at this time as to operations to be undertaken in the west (South Burma or toward Singapore) in 1944. | (j) Approve planning and preparations for the start of operations for the capture of Singapore with a target date of 1945, followed by the recapture or reoccupation of Southern Burma during the season 1945-46. This decision to be reviewed in the spring of 1944 in the light of the then existing German situation. |
| (k) Agree that the forces to carry out the operations from the East, including Southwest Pacific, will be provided by the U.S., Australia and New Zealand; operations to be carried out from the west to be with forces provided by Great Britain, except that special types not available to Great Britain will be added by the U.S. | (k) Agree that the forces to carry out the operations from the East, including Southwest Pacific, will be provided by U.S.[;] operations to be carried out from the west to be with forces provided by Great Britain, except that special types not available to Great Britain will be added by the U.S. The employment of Dominion forces will be a matter for discussion between all the Governments concerned. |
Appendix
Secret
Summary of Appreciation and Outline Plan for the Defeat of Japan
The following is a summary of CPS 83 (Appreciation and Plan for the Defeat of Japan). We have based the outline plan that follows on our best evaluation of what may have to be undertaken.
We have assumed that Japanese resistance will be continuously stubborn, and have taken no credit for a decline in the morale of the Japanese people or fighting services. Nevertheless, we do not believe that it will be necessary to carry out the whole program of operations in order to defeat them. Even if Japanese morale remains high, at some point the continuous process of weakening the enemy’s forces and reducing his war potential will cause a rapid decline in his ability to fight and a consequent acceleration of our advance. Since it is impossible to forecast the stage of the operations at which this critical point will be reached, we have throughout endeavored to make the plan sufficiently flexible to permit of considerable acceleration at any stage.
Basic conclusions
We summarize below the basic conclusions of our appreciation:
To achieve the ultimate defeat of Japan we must destroy her capacity to resist and this may well involve the invasion of Japan.
The security of the Japanese position in the Pacific depends primarily on the Japanese Fleet and Air Forces. We must therefore destroy them as soon as we can.
Heavy and sustained air bombardment of Japan proper should cripple the Japanese war industry and destroy her ability to continue her main war effort. It might cause the surrender we demand but we cannot rely on this. In any case, air bombardment of this nature is probably an essential prelude to bring about the defeat of Japan.
To bring about the sustained air offensive against Japan we shall almost certainly require the use of China and/or Formosa as the bases for our long-range bombardment. These two areas will also go a long way towards meeting our requirements for mounting invasion forces. We shall require Chinese assistance in seizing and holding the area in China required for our air bases.
To secure and develop airfields on the mainland of China, it will be necessary to acquire ports in China. So far as we can see, Hong Kong will be the most suitable port to open initially.
We therefore require a sea route to China and/or Formosa and the interruption of the enemy’s lines of communication thereto. This will entail control of the South Japan and South China Seas. The best route of advance from the East lies through the Mandated Islands, and then either through the Celebes and Sulu Seas or north of Luzon. The best route of advance from the West lies through the Straits of Malacca.
In reaching these conclusions we have been guided by certain principles, which in turn should be applied throughout the execution of the plan:
a. We should attack Japan along as many lines of advance as are profitable, in order to make use of our superior forces and to extend the enemy defense.
b. Every possible means of taking short cuts to our objectives should be adopted. The superior forces, particularly Air Forces, available to us and the opportunities for surprise should enable large and bold steps to be taken without unacceptable risk.
c. Shortage of bases will initially restrict our possible lines of advance. We should therefore take the first opportunity of securing additional bases from which to deploy our superior strength.
d. Our strength, particularly in the air, should be concentrated against Japan’s weaknesses, which lie in her shortage of aircraft, warships, shipping and oil.
Conversely extensive campaigns against Japanese land forces in difficult country, where we cannot use our own forces to the best advantage, should be avoided until they have been weakened by lack of supplies and support from the Japanese navy and air forces.
Whenever possible, we should, in fact, aim at leaving Japanese land forces in possession of outlying territory, in order that they may continue to be a liability to Japanese shipping, air and naval forces.
e. Wherever practicable, direct attacks on our objectives should be aided, and if possible preceded, by attack against Japanese communications leading to them. The extremely extended nature of their communications, together with the notorious inability of the Japanese to deal with the unexpected, are likely to render such methods very profitable.
f. Since shipping is unlikely to be a limiting factor after the defeat of Germany, our lines of advance need not necessarily be selected so as to take the shortest route from the U.S. or U.K. to our ultimate objective, but rather the one most easily established and protected.
g. We should devise every possible means of exploiting to the full, the vast technical and numerical air superiority which we shall enjoy over the Japanese after the defeat of Germany.
h. Whilst recognizing that every effort must be made to retain China in the war and to develop her bases and land forces, our plans should retain the necessary flexibility to enable our program against the Japanese to be continued if China should drop out of the war or prove less effective than we now hope.
i. Whilst being prepared to achieve our aims without Russian assistance, our plans should nevertheless retain the necessary flexibility to exploit the situation fully if Russia should join in the war at any stage.
j. We cannot forecast the date at which Germany will be defeated. To minimize the delay in turning the full weight of our offensive against Japan after the defeat of Germany, the bases from which our initial advances are to be launched should be developed as soon as possible and plans for reorganization and redeployment made without delay.
General concept of the war
Applying these principles to the basic conclusions set out above, the general concept of the war which emerges is as follows:
First phase – Action prior to capture of a port in China and/or Formosa
In the East, our main effort should be through the Mandated Islands. Until we are ready to launch this main effort, we should maintain increasing pressure on the Japanese by means of offensive operations in the Solomons-New Guinea area and in the Aleutians. When we turn to our main effort these latter operations should become subsidiary, and should only be undertaken insofar as they are necessary for the success of our main effort.
Having completed our advance through the Mandated Islands, we should then proceed either to the South Philippines or to the north of them. Our choice should be made in the light of whichever course will most quickly achieve our object of reaching the China Coast and/or capturing Formosa.
In the West, we should maintain China and build up our air forces there by stepping up the air supply route from Assam and by operations to clear Northern Burma, thus permitting the opening of a land route to China.
Meanwhile we should make preparations in India for the launching of the major campaigns to recapture the whole of Burma and to break into the Japanese perimeter from the west by the recapture of Singapore.
Once that has been accomplished we should make our way through the South China Sea towards the coast of China and Formosa.
Coordination
To integrate our advances from the West and the East, the timing of the various operations should, if possible, be so arranged that they afford one another the maximum amount of mutual assistance at each stage.
For our advance from the East, & very large fleet, but comparatively small land and shore-based air forces will be necessary, and therefore comparatively little shipping, until we have completed our advance through the Mandates, when our ground and land-based air forces may well be of a very large order.
Our advance from the West, on the other hand, will require large land and air forces and much shipping, but probably a considerably smaller fleet than in the case of our advance from the East.
Our advance from the East should provide opportunities for bringing the Japanese fleet to action in favorable circumstances. It will enable us to threaten and strike at Japan herself, and, in conjunction with air forces from China, to strike at the focal point of the Japanese sea communications in the Yellow Sea-Formosa areas. This will greatly assist our advances from the west by forcing the Japanese fleet and air forces on to the defensive in their home area and by enabling our forces in the east to strike at the Japanese communications leading to the objectives of our advance from the west.
In executing our advance from the west, and after completing the capture of North Burma (Course A), two courses of action remain open to us in the west.
Course B – (Recapture of South Burma followed by recapture of Singapore) probably offers the best chance of maintaining China in the war by insuring that the overland supply route is developed as early as possible and with the greatest reliability. On the other hand, the delay in the recapture of Singapore is likely to mean that our advance to open the sea route to China would have to be undertaken from the east alone, and would receive little aid from the west.
Course C – (Recapture of Singapore, followed by recapture of South Burma) would enable a much greater degree of coordination and mutual assistance to be achieved in the later stages of our two advances since we should expect to reach Singapore and advance therefrom a year earlier. It would stretch Japanese resources over a wide area and would enable the British Fleet to operate off the China coast. Our land and air forces could also be moved up the South China Sea along routes far removed from the main enemy naval strength in Japan.
On the other hand, we should run the risk of delaying the development of the overland routes to China, although there would be no appreciable delay if all operations go according to plan.
Irrespective of whether the advance from the east or the west approaches China first, it is unlikely that we shall be able to capture Shanghai direct. In conjunction with shore-based air support from China, and Chinese land forces, we might, however, be able to undertake a direct assault on Hong Kong, subsequently taking Formosa.
If the capture of Hong Kong is impracticable, we should endeavor to seize Formosa first, or, if this too is impracticable, Luzon.
If neither of these can be seized direct, we should assault Hainan and if possible one of the Ryukyus.
If the above are impracticable we should continue operations against the South Philippines and complete our control of the Celebes and Sulu Seas, subsequently carrying out our program to capture a port in China and/or Formosa.
Second phase – Action subsequent to the capture of a port in China and/or the capture of Formosa
This phase will involve overland and amphibious operations in China and direct air and naval action to weaken Japanese capacity to resist. It will probably culminate in the invasion of Japan.
If we are established in Hong Kong before Formosa has been captured, we shall be in a position to build up the necessary land forces in China, secure the air bases most accessible from Hong Kong, and start the bombing of Japan at long range.
If, on the other hand, we capture Formosa before Hong Kong, or find that the Chinese assistance on the mainland is disappointing, the bombing of Japan can start from Formosa.
It is possible that, with the assistance of sea-borne air forces, Japan may be sufficiently weakened to enable us to invade her when our bomber offensive has been developed from either Formosa, or the area most accessible from Hong Kong.
On the other hand, to bomb Japan effectively we may have to move further northwards from Hong Kong in order to use the area up to the line Wenchow-Nanchang-Changsha.
From the invasion point of view, we may possibly have to secure the Shanghai area, and if this is the case, we should be well placed from our positions in Hong Kong and Formosa to undertake such an advance both overland and coastwise.
If Chinese assistance proves to be effective, our main effort will probably be made overland. If, on the other hand, it is disappointing, our main effort would be concentrated in amphibious operations along the China coast as far northwards as necessary.
Subsidiary and alternative lines of advance
Meanwhile, subject to the requirements of our main advance, we should:
(i) undertake subsidiary operations along the Malay Barrier to bring increased pressure to bear on the Japanese;
(ii) prepare plans and bases for the capture of the Northern Kuriles and the reinforcement of Petropavlovsk, in order to secure a sea route to Russia in the event of her entering the war;
(iii) prepare plans and bases for the capture of Hokkaido should the opportunity arise for assisting our bombing or undertaking our invasion of Japan from this direction, possibly in conjunction with Russian action from the Maritime Provinces, Sakhalin or Petropavlovsk.
Outline plan
Based on our appreciation, we indicate below an outline plan for operations against Japan:
| Action in the West | Action in the East |
|---|---|
| Serial 1 – Up to November 1943 | |
| Development of air routes to China. Holding operations in North Burma and China. | Offensive operations against Solomons and New Guinea. Offensive operations against the Aleutians. |
| Serial 2 – November 1943 to May 1944 | |
| Offensive operations in Northern Burma and on Arakan coast. Developing Northern routes leading to China. | Offensive operations against Gilberts and Marshalls. Subsidiary operations in Solomons and New Guinea and air operations from the Aleutians. |
| Serial 3 – June 1944 to November 1944 | |
| Holding operations in Burma. | Offensive operations against Carolines. Subsidiary operations in New Guinea area. |
| Action in the West | Action in the East | |
|---|---|---|
| Serial 4 – November 1944 to May 1945 | ||
| Course B (favored by U.S.) | Course C (favored by British) | |
| Offensive operations in North Burma and capture of Rangoon. | Offensive operations in North Burma. Offensive operations against Northern Sumatra and Malaya. | Offensive operations against the Pelews and possibly Marianas. Subsidiary operations in the New Guinea area. Commence offensive operations against South Philippines.* |
| Serial 5 – June 1945 to November 1945 | ||
| Holding operations in Burma. | Holding operations in North Burma. Continue offensive operations in Malaya and against Japanese communications to Burma. | Continue offensive operations against the South Philippines. – or Offensive operations against Luzon, Formosa or Ryukyus. |
| Serial 6 – November 1945 to May 1946 | ||
| Complete offensive operations to clear Burma. Offensive operations against N. Sumatra and Malaya. | Offensive operations against North Burma and Rangoon, subsequently clearing the whole of Burma. Offensive operations against Camranh Bay.† | Continue offensive operations [against the] South Philippines. – or Launch offensive operations against Hong Kong or Formosa (if not already captured). |
| Serial 7 – During the remainder of 1946 | ||
| Complete capture of Malaya. | Launch offensive operations against Luzon, Formosa, Hong Kong, Hainan and/or Ryukyus from East and West. – or Establish the strategic bombing force in China and/or Formosa. |
Serial 8 – From 1947 onwards
Establish the strategic bombing force in China and/or Formosa.
- Bomb Japan.
- Invade Japan.
*If conditions are favorable, it may prove possible to bypass this objective.
†If conditions are favorable, it may prove possible to bypass this objective.
