TERMS OF REFERENCE: NIE-37: LIKEIHOOD OF A SOVIET ATTACK ON JAPAN

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP79R01012A001100030010-4
• Release Decision: RIPPUB
• Original Classification: T
• Document Page Count: 6
• Document Creation Date: December 16, 2016
• Document Release Date: April 19, 2005
• Sequence Number: 10
• Publication Date: May 16, 1951
• Content Type: NE

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CONFIDE
1012A0011000300104
CENTRAL INTELLIGENC-qV- A GENCY
25X1A9A
16 May 1951
SUBJECT: TERMS OF REFERENCE: NIE-37: LIKELIHOOD OF A SOVIET ATTACK ON JAPAN
THE PROBLEM
OFFICE OF NATIONAL ESTIMATES
in an invasion, the chief burden would obviously be upon the USSR.
J
That Soviet and US forces in the Far East at present will remain roughly the
same for the remainder of 1951.
PART ONE: SOVIET CAPABILITIES FOR INVADING JAPAN
It would be impossible to analyze the likelihood of Soviet invasion of Japan
without estimating the USSR's own evaluation of its capabilities for succefsful in-
vasion. Thus in order to arrive at an accurate and realistic estimate of -bviet
capabilities we must examine the situation from the Soviet point of view. This
implies that the USSR will give due consideration to the enemy forces which they
know are available or can be made available during 1951. It further implies that
the whole of Soviet Far Eastern capabilities cannot be made available for invading
Japan, but that some portion must be withheld to meet overriding requirements else-
where in the Far East.
I. WHAT C( KIST FORCES ARE AVAILABLE?
A. What is Soviet strength in the Far East?
1. Order of battle (at divisional level), location, and combat-effective-
ness of Soviet ground forces?
2. Strength and disposition of Soviet naval forces, merchant fleet, and
auxiliary forces? Capacity of merchant shipping?
3. Order of battle of Soviet air forces and air facilities?
To assess the likelihood of a Soviet attack on Japan during 1951.
While it seems advisable to consider the possible use of other Communj:st forces
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B. What portion of the above forces would be available for invasi n of
Japan in 1951, giving due consideration to Soviet needs elsewhere in the Par East?
In view of the necessity of defending key strategic and industrial areas ii the
Far Eastern USSR, supporting Communist China, garrisoning Dairen, etc., th-3 USSR
obviously could make available only a portion of its overall strength.
C. What other Communist forces might be available?
1. Japanese POW troops -- political reliability?
2. Chinese Communist troops. Could any of these be used whils> the
Korean campaign was on? In any case, would the USSR either need Chinese ground
forces or consider it politically desirable to permit such forces to participate in
invading Japan?
II. WHAT ARE THE CAPABILITIES OF THE ABOVE FOI ES?
A. What are Soviet ground force waterborne assault capabilities? Airborne
capabilities?
B. Would Soviet naval forces be able to (1) secure the contiguous waters
around the invasion area; (2) screen a landing; and (3) protect the lines cif couxuni-
cation?
C. Could the Soviet air forces achieve and maintain local air superiority
over the beachhead, interdict the land and sea approaches, and protect Soviet staging
bases, and lines of communication? Since this would probably be a critical factor in
a Soviet decision, such factors as air facilities, sortie rates, and combat effec-
tiveness might be analyzed in detail.
D. What are Soviet capabilities for mounting and maintaining an amphibious
operation of the size indicated above? How much amphibious and airborne lift could
the USSR assemble?
III. OTHER FACTORS BEARING ON SOVIET CAPABILITIES?
A. How would the USSR logistically sunv v and resnrn,ly an invasion force,
especially with POL? Are Soviet Far Fastern stockpiles adequate for the purpose and
for how long? How much II Soviet shipping will be necessary with due allowance for
attrition?
B. What landing beaches and ou r st could the Soviets seize initially in order
to bring in the bulk of the assault forces? Are these adequate?
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C. How would the poor weather, especially around Hokkaido, affect invasion
prospects? When would be the best time of year to invade?
D. Could the USSR expect to achieve tactical surprise? How much yarning W-,;ht
the US expect to achieve and how might this affect Soviet capabilities?
E. Would the USSR estimate that possible diversions, such as a si.-nultaneou
Chinese Communist threat or invasion of Formosa or Hong Kong would split t3 air and
naval forces? Might a simultaneous offensive in Korea be expected to pin town the
Eighth Army and hamper reinforcement of Japan?
F. Would the majority of Japanese actively support the US forces :wd how
would this affect Soviet capabilities? How significant an increment to Soviet capa-
bilities would be Japanese Communist subversive, sabotage, and guerrilla activities?
I9. WHAT ARE THE POSSIBLE INVASION ROUTES?
Where and how could Soviet (and other Communist) forces invade Japan? In-
vasion of Kyushu from South Korea, invasion of Honshu across the Sea of Japan, or
invasion from the north might be considered, among other possibilities. M-at is the
most feasible invasion pattern (a) assuming the US still holds South Korea, (b) as-
suming US loss of Korea? Would not the overriding necessity for providing land-based
air cover almost require invasion from the North?
V. COULD THE USSR SUCCESSFULLY MAINTAIN AND EXPAND ITS INITIAL LODGEME~I',' IN JA AV"
We consider this a crucial question on which any Soviet estimate might well
turn. Assuming the Soviet forces could seize a substantial beachhead, cou:i they
expand it and occupy the remainder of Japan?
A. How vulnerable are the long Soviet overland and seaborne supply- lines.
including the Trans-Siberian, to U5 interdiction following an invasion?
B. Could the Soviet forces expect to maintain themselves logistically in the
face of probably increasing US surface and submarine attacks, carrier stri}-es, and
other air attacks on invasion shipping, key ports, and rail lines, perhaps including
use of atomic bombs?
0. Could the USSR expect to build up decisive strength in the beachhead faster
than a US defensive buildup, including forces withdrawn from Korea? Assuming the
capture of Hokkaido, could the forces on Hokkaido then be expected to invade, Honshu
successfully?
D. Does the terrain, expecially in Hokkaido and Northern Honshu, favor the
invader? Are there defensive bottlenecks which would facilitate the defenue of Honshu
in particular against invasion from the Worth?
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VI. HOW DOES THE KOREAN CAM-AIGN AFMT SOVIET CAPABILITIES?
To what extent does US Involvement in Korea make it more feasiblet'or the USSR
to invade Japan? On the other hand, to what extent would Communist seizure of Korea
facilitate invasion of Japan? Would it make possible a two-pronged invasion from Kcorea
as well as the North?
VII. CONSIDERING THE 4BOVE FACTORSISOW WOULD THE USSR ESTIMATE ITS CAPABILITIES TC?
INVADE AND OCCUPY JAPAN?
In examining this problem, we should consider what portions of Japan the USSR
might estimate it could successfully seize and hold. Hokkaido alone, Hokkido plus
northern Honshu, etc.?
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PART II: PROBABLE SOVIET -INTERTIONS
I. WHAT ARE SOVIET OBJECTIVES RE Jam?
How does Japan fit into overall Soviet strategy in the Far East? Fo:? example
wasn't the Korean invasion largely intended to provide a stepping stone anti pose
threat to Japan? How important is control or neutralization of Japan to t-e USSR?
To what extent does the Kremlin fear Japanese rearmament in alliance with US?
To what extent might the USSR hope to utilize Japan itself, militarily and eco-
nomically?
II. TO WHAT EXTENT MIGHT THE USSR HOPE TO ACHIM ITS OBJECTIVES BY M y SHORT
OF EARLY INVASION?
Obviously the USSR seeks to pose a continuing threat to Japan, CouL the U;S:
expect by threats, subversion, propaganda, etc. to: (1) achieve first a neutral and
then a Soviet-dominated Japan; or (2) sufficiently soften Japan for hies nttack7!
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Might the USSR expect the US to eventually pull oit
of Japan, leaving it more exposed to Soviet attack?
III. WHAT IS THE EVIDENCE -- PRO AID CON -- RE SOVIET INTENTIONS TO TNVAD , JAPAN
IN 1951?
To what extent do Soviet Far Eastern preparations appear defensive rather than
offensive and vice versa? To what extent do these preparations appear ge&:?ed to a
1951 invasion, as opposed to later?
IV. WHAT IS THE PROBABLE SOVIET ESTIMATE OF THE US AND WESTERN REACTION SOMT
INVASION OF Jam?
A. Would the USSR estimate that it could invade Japan without start~.ng a
general war? Would it estimate that the US would seek to confine hostilites to the
Far East?
B. Even if willing to accept the risk of war with the US, would the USSR
estimate that it could split the US from its Allies? If this were possible, wou]iii
it be desirable from the Soviet point of view?
C. Would the USSR estimate that MIX the US would make an all-out effort to
hold Jajapan, including deployment of large naval and ground forces, and strf:tegic f:ir
attackss,at least on Soviet Siberia?
D. What would be the political and psychological advantages and disaiivantagms
of a Soviet invasion in 1951?
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V. IF THE USSR ESTIMATED THAT IT COULD NOT SEIZE ALL OF JAPAL BUT ONIZ"T
NORTHERN PORTION. HOW MM WOULD THIS AFFECT SOVIET INTENTI0NS?
VI. WHAT NEW DEVELOPMENTS MIGHT SERIOUSLY AF MT SOVIET INfENtIONS?
A. Would the USSR probably invade Japan in event of general war is 1951?
In this event how would a reduction in i18 forces in the FE affect Soviet L'Itentioxs,
B.
What would be the effect of accelerated Japanese rearmament on Soviet
intentions?
0.
What would be the effect on Soviet intentions of a US disaster in
D.
What would be the effect on Soviet intentions re Japan if the Ua widened
the scope of the Korean war by attacking Communist China?
E. How would Soviet intentions be affected by a reduction of US forces in
the Far East, presumably following a de facto or negotiated restoration of the
status quo in Korea?
VII. CONCLUSIONS
A. In the light of (4t) the probable Soviet estimate of their own ca: mbiliti.er
(A) the probable Soviet estimate of the situation resulting from an attack on Japan-
and (3) overall Soviet intentions globally as well as in the Far East., what is the
likelihood of a Soviet invasion of Japan in 1951?
B. What new developments might lead to a major change in the above estimate
of Soviet intentions?
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