NO. "
_ DIRECTOR
aldLXS COLLECTION AND DISSEUIKATION.CIA
PROBABILITYOMMUNIST ASSAULT ON JAPAN1
OA HISTORICAL REVIEW PROGRAM RELEASE IN FULL
SE- II Publi-Jwd1
CENTRAL INTELLIGENCE AGENCY
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PROBABILITYOMMUNIST ASSAULT ON JAPAN1
1
Published1
The intelligence organizations of the Departments of State, the Army, the Navy, the Air Force, and Joint Staffwith the Central Intelligence Agency in producing this estimate. The members of the Intelligence Advisoryconcurred in this estimate onxcept for the differing opinions set forth inn page 4.
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PROBABILITYOMMUNIST ASSAULT ON JAPAN1
THE PROBLEM
To examine Communist capabilities for an assault on on Japan and to estimate the probability of such an assault during the remainder*
ESTIMATE
CAPABILITIES'*
^i. We estimate that the USSR and Communist China have the capability of launching an assault of thc following scale and nature on Japan:
' (a) Substantial air and submarine attacks on Allied lines of communications, ports, and bases;
1 (b) An initial amphibious assaultorce of two to three divisions, coupled with an airborne landingroops;
yollow-up landing (providing the initial assault
echelons succeed in seizing port facilities) by up to six divisions;
* This estimate does not consider the opposition of US/UN ground, naval or air forcesoviet assault upon Japan.
ee Annex "A" for fuller treatment of Communist
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TOD SKCftET
y (d) Possibly build-uptrength of fifteen divisions
in Japan0 days, and twenty-five divisions0 days, provided Communist forces succeed in establishing sufficient beachheads and adequate port facilities, and furthermore that optimum conditions prevail throughout the operation with regard to weather, shipping, and port facilities in the USSR and and in Japan.
Sufficient Soviet ground forces are available for an assault on Japan, but the Soviets might also make use of Chinese Communist troops presently disposed in Manchuria and of Soviet-sponsored Japanese POW's. If such non-Soviet forces were employed, however, they would have to be supported by large-scale Soviet air and naval forces. /
INDICATIONS
here is no reliable evidenceoviet intent to undertake an early invasion of Japan. There are reports alleging Sino-Soviet plans to initiate expanded hostilities in the fail. However, these reports are of unknownsince the primary source would probably not have access to high-level planning. Moreover, these reports are not substantiated by other intelligence. In particular there is no recent evidence of "pre-invasion" preparations such as extensive amphibious training, assembly of water lift or the deployment of forces to staging areas. Finally, these reports may well be inspired by the Communists as part of the psychological warfare effort to support their position on the Korean cease fire and the Japanese Peace Treaty.
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PROBAHIMTIKS
vailable indications do not suggest that an early Soviet invasion of Japan is probable. However, these indications would not in themselves necessarily be conclusive. Since the outbreak of hostilities in Korea, the long-range Soviet program to make the Soviet Far East loglstically andself-sufficient has apparently been accelerated. In view of the current readiness of the USSR for military operations, it is possible that there would be no indications of the preparations for the assault except the final assembly of ships for combat loading, which might be detected.
he Kremlin almost certainly estimates that an assault on Japan would Involve notocal war with thc US, in which thc US might well use atomic weapons, but also the strong probability of general war with the US,S strategic atomic attack on the USSR. Thesewould almost certainly result also from an assault on Japan by Chinese Communist troops and Soviet-sponsored POW's since such an assault could not bewithout the participation of Soviet naval and air forces.
he USSR might take the risk of precipitating general
war if it foresaw an immediate threat to its vital Interests.
We do not believe that the Kremlin is likely to conclude
uJibin
T^atv-flmr/ot> Japanese rearmament alone constitutesa--
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It is the opinion of the majority of the members of the Intelligence Advisory Committee (State, Army, Air Force and the Joint Stall) that an invasion of Japan might also resultremlin decision to initiate general war on thc basis of global considerations. The majority concludes, therefore,oviet assault on Japan1 is unlikely except in the event of global war.
withvu.generalt is unlikely that the Kremlin wouldajor campaign against Japanince the Kremlin probablythatampaign would eventually result In the loss of its Far Eastern Fleet, the loss of its invasion force, the inability further to support the Chineseand thc exposure of Manchuria and thc Maritime Provincesll without producing decisive results from
a global point of view. ftfrftWOteMt Navalin tlrrs "Oplniom-
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ANNEX A
SOVIET CAPABILITIES TO INVADE JAPAN
1. Assault Capabilities. Xhe USSR probably has theof launching an amphibious and airborne attack on Japanorce up to ninemmediatelyor concurrently with this attack, the USSR could launch heavy naval and air attacks on Allied lines ofports, and bases. The initial amphibious assault probably could be madeorce of two to three divisions and could be coupled with an airborne landing of upirborne troops. After the airborne or amphibious assaulthad seized the port facilities, the remainder of thelift (up to six divisions) could proceed with their landing over docks. Assuming that the USSR were successful inbeachheads in Japan, they could probably build uptrength ofivisions in Japan0 days andivisions0 days.**
* oviet division totals0 men.
t is the view of the Director of Naval Intelligence that this sentence should be stated as follows:
Assuming that the USSR were successful in establishing beachheads in Japan, they could possibly build uptrength ofivisions in Japan0 days andivisions0 days, provided Communist forcesin establishing sufficient beachheads and adequate port facilities, and furthermore that optimum conditions prevail throughout the operation with regard to weather, shipping, and port facilities in the USSR and in Japan.
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2- Logistic Support. Approximately one-half of the total one million gross registered tons of shipping which the Soviets have ln Far Eastern waters could be mustered toully equipped divisions and would be adequate tolow of supplies. Stockpiles, except for POL, are believed to exist in the USSR east of Lake Baikal sufficient to supply Sovietln the Far East for one year. Information is notto determine how long stockpiles of aviation gasoline might last. Existing stockpiles of aviation gas could beby shipments from the western USSR which wouldrastic reduction in the transportation of otherrequirements to the Soviet Far East.
Support. The total Soviet Far Eastern Floct2 cruisers,atrolmphibious type craft. USSRa substantial threat, at least initially; however,in the Far East are especially vulnerable fromof limited bases for operations, and the necessitymineable straits to reach the Pacific Ocean orSea. Two of these four straits are closed by iceLittle is known of the condition of theamphibious type craft which are now over five yearsSoviet Far Eastern Fleet could receive limitedvia Ihe northern sea route during the six to eightroute is open during the summer. However, suchprobably would be detected.
Soviet
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(i) The Soviet Far Eastern Air Forces have an estimated Table of Organization and Equipment strength
ombat aircraft, primarily of Worldypes, (Actual strength is estimated to be aboutercent of this authorized strength, but it is believed that all units could be brought up to full strengthelatively sliort period of time.)arge proportion of this force would have to be redeployed to bring it.within operational range of Japan,inimumombat aircraft could be employed in the initial effort in Japan, and this force could be materially augmented, if required,eriod of time. Under conditions of sustained combat, it is estimated that not more thanercent of the combat aircraft assigned could be kept operational. This percentage might behigher for transport aircraft. Composition of theair force is problematical, but it probably wouldarge proportion of light bombers and long range fighters, as well as mine and torpedo squadrons, andsmall numbers of medium bombers.
(ii) Sortie capabilities, at least in the early stages of the attack, woulder day. In calculating sortie capabilities, it is considered that maximum rates per month will beer assigned light bomber and fighterespecially since the operations will involve longer ranges than were required of Soviet units in World War II. Sortie rates may be less thaner month for units stationed on the China coast, North Korea, or the Maritime province. Extremely short range operations could be undertaken only from bases in southern areas ofigh level of combat attrition would result in even lower sortie capabilities than have been indicated.
(b) Chinese Communist. The Chinese Communists haveircraft, includingircraft of the North Korean Air Force andircraft
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f which are jet fighters) of undetermined subordination. Thc bulk of these could be used in an assault on Japan. Kyushu and the southwestern tip of Honshu could be attackedarge proportion of the enemy aircraft operating out of Shanghai, Tsingtao, and Antung.
5. "Volunteer" Forces. In addition to regular Soviet forces, thc Communist ground forces used for an assault on Japan could be composed of Chinese Communist troops presently disposed in Manchuria and/or Japanese ex-prisoners of war not repatriated to Japan by the Soviets. Although the existenceapanese force has not been confirmed, it is estimated00 Japanese personnel capable of mUitary service are held in Communist-controlled territory. However, we do not believe that the Soviets would estimate that bysuch "volunteer" forces they could successfullySoviet overt participation in an assault on Japan,in view of the fact that such forces would have to be supported by large-scale Soviet air and naval forces.
Original document.
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