J.C.S. Files

Report by the Combined Intelligence Committee1

Enclosure to C.C.S. 643/1

Estimate of the Enemy Situation, Pacific–Far East

the problem

1. To estimate the enemy situation and intentions in the Pacific and Far East.


2. Political and psychological. (See Appendix “A.”) Japan has sought to enlist the support of her most populous conquered areas by powerful propaganda and by grants of specious independence. For the present, Japan desires to avoid war with the U.S.S.R. in order to be free to direct all her energy against her enemies.

As a result of their fundamental beliefs, the morale of the Japanese populace, and especially of the armed forces, has remained relatively high, but a continuing series of sharp defeats will tend further to confuse and bewilder the Japanese. Such defeats, combined with a collapse of Germany, might conceivably cause a reshuffling of the ruling clique followed by an attempt to secure a negotiated peace. Japanese propaganda has already shifted from self-assured offensive to defensive.

3. Economic factors. (See Appendix “B.”) Production of high-priority armament items such as aircraft may continue to expand for some time, even though the rapid growth of Japan’s basic industry has been levelling off since the beginning of 1944. Further substantial growth of the Japanese steel and other basic industries is believed impossible in the light of the present Japanese shipping position. Shipping is now barely adequate to sustain current production rates in the basic industries, and sinkings exceed launchings. The largest and most essential economic commitment for shipping is within the Inner Zone.* Japan is continuing to develop raw material sources in the Inner Zone in an attempt to achieve self-sufficiency there, but is unlikely to achieve this goal. She is particularly dependent on the Outer Zone for oil. Inner Zone production and stockpiles of fuel oil are at best estimated as sufficient for about nine months but may be much less. In other essential raw materials not available in sufficient [Page 268] quantity in the Inner Zone, Japan is believed to have stockpiles to carry her for longer periods.

Japan’s civilian supply position is stringent but not yet critical with respect to food and is generally bad and deteriorating with respect to other commodities, e.g., clothing.

4. Military factors. (See Appendix “C”) Realizing that the war potential of her enemies is increasing much more rapidly than her own, Japan has been compelled to adopt the strategic defensive. She hopes that tenacious resistance along successive lines of defense may eventually result in war weariness and possible division among the United Nations, which would enable her to conclude a satisfactory peace. In the past year her air force has deteriorated in quality of personnel and has operated less aggressively; her navy has suffered serious losses; only her ground forces have maintained their strength and fighting qualities.

Although Japan will continue to use caution in the employment of her air power and especially her battle fleet, we believe, nevertheless, that Japan now intends to make vigorous efforts to resist any Allied penetration of her inner defense line Japan–Formosa–Luzon–Mindanao. Her ground forces will offer maximum resistance at all points with little regard for losses; her air power will be committed to a scale of defense proportionate to the strategic importance of each area, and her battle fleet will attack should local circumstances develop which seem to offer opportunity for an effective blow.

In the Bonins, at Palau, and at Halmahera local Japanese ground forces will resist to the maximum extent of their capabilities, but without strong naval and air support.

5. Intentions in specific areas. (See Appendix “D.”)

Japan Proper. As the war draws nearer to Japan we may expect to find an increasingly large percentage of her naval and air forces based nearby and all home defenses considerably strengthened.
Northern Pacific. Japan will continue her present policy of gradually strengthening her garrisons and other defenses in the Kuriles and Japanese Sakhalin.
Manchuria. In view of the Soviet threat, Japan is unlikely to release any appreciable ground forces from Manchuria unless they can be quickly restored. She will continue to maintain a strong defensive position there, but is unlikely to undertake any offensive action unless she becomes convinced that the U.S.S.R. is about to enter the war against her.
China. We believe that the Japanese are now conducting operations with the intentions of neutralizing Allied air forces in China and also of establishing overland communication from Manchuria to south China. Japan hopes, by such moves, to improve her strategic position in central and south China.
Burma. The Japanese will continue to attempt to deny the Allies a land route to China and to maintain their position in Burma as an anchor for their western perimeter defenses. They will only undertake limited offensive action for the purpose of breaking up Allied operations.
Malaya–Sumatra. Although this area is of great importance to the Japanese, both for its own resources and as a barrier on the approaches to the South China Sea from the west and south, we anticipate no substantial reinforcement of it until a major threat is more clearly apparent.
East Indies. We believe that Japan will maintain her hold on the East Indies as long as possible, even though her sea communications should be severed.
Formosa–Luzon–Mindanao. The Japanese are busily engaged in strenuous efforts to reinforce this line. They will resist fiercely any penetration of this line, particularly the Luzon–Formosa area. They will accelerate the rate of reinforcement should the Allies occupy the western Carolines.
Central Pacific. In the Bonins, at Palau, and at Halmahera local Japanese ground forces will resist to the maximum extent of their capabilities, but without strong naval and air support.

6. A detailed estimate of enemy order of battle and deployment will be available as Annex “A” when required.2

Appendix “A”

Political and Psychological Factors

External politics.
General. Japan has propounded two powerful propaganda themes: “Asia for the Asiatics” and “The Co-Prosperity Sphere;” and has adopted such relations with neighboring peoples as she believes will contribute to the fulfillment of her plans. Following are the steps which have been taken, but they represent changes in form rather than in substance.
Relations with China. Japan has recognized the “independence” of China, as represented by the Nanking puppet government, and has sought to enlist Chinese nationalism in support of that regime by surrendering to it various foreign concessions, notably those at Shanghai.
Relations with subject peoples. Japan has granted “independence” to Burma and the Philippines, seeking to enlist the relatively developed nationalism of those countries in her favor; she has hinted that other occupied areas (e.g., Java) may receive similar grants of “independence;” and she has rewarded Thailand for cooperation by [Page 270] the cession of certain neighboring territory to which Thailand had some pretensions.
Relations with the U.S.S.R. There exists between Japan and the U.S.S.R. a basic conflict of interest. Japan’s concept of strategic security cannot be satisfied without gaining control of the eastern region of Siberia. For the present, however, Japan desires to avoid war with the U.S.S.R. in order to be free to direct all her efforts against her enemies.
Relations with the Axis. Japan’s connection with the Axis is a matter of expediency only. Her action will be coordinated with that of Germany only insofar as she believes that such coordination will contribute to the realization of her basic aims.
Psychology and morale. The Japanese, traditionally, are an intensely nationalistic and close knit family whose broad characteristics are a toughness of fiber and a fatalistic singleness of purpose. They have been taught that they are of divine origin, that the Emperor is directly descended from the god-founder of the nation and that the Japanese are divinely and infallibly guided towards the establishment of a new world order. The Japanese soldier is taught to give blind obedience and to regard death in the service of the Emperor as an honor. He is told that he is invincible and that to show weakness or to surrender is to accept disgrace.

As a result of these teachings, the morale of the Japanese populace, and especially of the armed forces, has remained high, but the unfavorable course of the war has caused some disillusionment. Moreover, since much of popular morale is based upon the theory of invincibility, a series of sharp defeats, as they are brought home to them, will tend further to confuse and bewilder the people as a whole.

Real power in Japan rests in the hands of small groups of leaders capable of exploiting the position of the Emperor. The collapse of Germany will have a tremendously depressing effect upon such leaders. This, combined with ever increasing United Nations pressure and approach to the homeland, might conceivably bring about a reshuffle of the ruling cliques followed by an attempt to secure a negotiated peace.

Official propaganda on the home front has lost its self-assured tone and determination to fight for existence is replacing exaltation in victory. The potential of the United Nations is admitted to be high, and the government has announced its intention to prepare for the defense of the homeland. Japanese withdrawals are admitted. It is implied that the Japanese have finished winning independence for other Asiatic countries and now must prepare to defend their own islands from frontal attack. The government is also preparing the Japanese people for more serious German reverses in Europe.

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Appendix “B”

Economic Factors

1. General. Though Japan may still be able to increase production of certain high priority armament items, e.g., aircraft, the expansion of her basic industry, which had ceased by the end of 1943, almost certainly cannot be resumed during this war. Lack of shipping is the most important limiting factor on the expansion of basic industry. Japan still depends on the Outer Zone for certain essential raw materials, especially oil. The Japanese have partially succeeded in reducing this dependence by stockpiling materials in the Inner Zone where nearly all Japanese industry is concentrated. The stockpiling program has fallen short because of lack of shipping.

2. Shipping. Japan’s shipping position is her most critical weakness and is deteriorating rapidly. We estimate that Japan now has much less shipping than she needs to carry out military commitments and at the same time to utilize her industrial capacity to the full. This condition will grow progressively worse. We believe, however, that Japan will not voluntarily abandon any strategic outpost because of a shipping stringency alone, but will accept a curtailment in her basic over-all industrial production by reducing the import of raw materials. Should the sinking rate increase, as it has increased in recent months, the Japanese would be forced to accept this import reduction proportionately sooner. Sufficient shipping should be available, if necessary, by diversion from trade, for essential troop movements.

We estimate that Japan will be unable to build more than 800,000 gross tons of steel merchant vessels in 1944, which is far behind the rate required to replace losses, and that her ship repair facilities are heavily overburdened. Great emphasis has been placed on wooden shipbuilding, but this program is not believed to be progressing as well as planned and could not, in any event, offset the discrepancy between losses and construction of steel ships. Japan’s shipping position would be relatively easier were she cut off from the Outer Zone.

3. Petroleum and other raw materials. In general, Japan’s industrial machine is dependent upon raw materials which must come from outside Japan Proper and thus the continuance of supply depends upon transportation. The most essential raw material contribution from the Outer Zone is oil. Other critical materials which Japan obtains from the Outer Zone include nickel, chrome, iron ore, manganese, lead, copper, zinc, bauxite and phosphates. Her dependence on the Outer Zone for these materials is however less than in the case of oil either because of the existence of relatively large stockpiles or the possibility in some cases of increasing Inner Zone supplies or of substituting other materials.

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Among petroleum products, Japan’s position is weakest in fuel oil. Inner Zone production and stocks are believed sufficient for about nine months and estimated present over-all production roughly balances consumption at the present calculated scale. Furthermore, about 75 percent of production is in the East Indies. Japan is developing new synthetic facilities in the Inner Zone, but present fuel oil output there would, we estimate, operate her naval fleet and merchant marine at less than one-third their present rate of activity, if stocks are not drawn upon. In aviation gasoline, Japan is similarly dependent upon the East Indies, 80 percent coining from there, but stocks, chiefly in the Inner Zone, are believed sufficient for somewhat more than a year at the present rate of consumption.

Japan’s tanker fleet has been reduced far below the minimum tonnage required to move fuel oil and aviation gas out of the East Indies to all consumption centers, and the deficit has been only partially offset by diversion of dry cargo vessels to oil-carrying. We believe that Japan will continue this diversion at the expense of other cargoes in order to keep the oil line full and moving.

Although about 20 percent of Japan’s iron ore is now derived from Outer Zone areas, we believe that Inner Zone production, most of which is outside Japan Proper, could fill all essential needs. Nearly all of Japan’s coal supply is in the Inner Zone, but more than 50 percent of it lies outside of Japan Proper. Thus iron ore and coal constitute the greatest burden of Japanese shipping. Japan is almost completely dependent on north China and Manchuria for coking coal since the supplies available to her elsewhere are generally of too poor quality to make high grade coke without the admixture of the coal from north China.

Stockpiles of bauxite and the possibility of producing alumina from inferior ores in the Inner Zone reduce Japan’s dependence on bauxite supplies from Bintan Island (Malaya) and Indochina. Though Japan’s copper stockpile is relatively small, she produces more than half her requirements at home. The lead stockpile, supplemented by Inner Zone production, would last at least a year. Japan’s zinc position is more stringent; the Inner Zone produces not more than two-thirds of Japan’s requirements and stocks are believed to be low.

Japan’s major source of nickel is Celebes and if this source were cut off her position would be difficult. A conservative use pattern probably has been observed, however, and we believe that the full effects would not be felt in less than a year. The first results of a sharp reduction in use of nickel would be impairment of the quality of war material.

In chromium and manganese, Japan’s position is believed to be somewhat better. For both, Inner Zone production, plus stocks, is believed sufficient for more than a year’s consumption. The Philippines [Page 273] are the major source of both, contributing a large portion of new chromium and nearly 40 percent of the new manganese.

The comparative dependence of Japan on specific Outer Zone areas is in the following order:

Sumatra: Fuel oil and aviation gasoline.
Borneo: Fuel oil.
Philippine Islands: Chrome, manganese, copper.
Celebes: Nickel.
Bintan Island: Bauxite.

4. Industry. Japanese industrial production expanded generally up to the beginning of 1944, when it levelled off because of basically restrictive factors (e.g., lack of shipping) which the Japanese are not expected to overcome during this war. However, production of certain high priority finished products, such as aircraft, continues to increase. Japan will attempt to increase the production of such instruments as fire control gear, radar, and other types of precision electrical equipment, but because of technical and organizational difficulties, we believe that she will not be able to accomplish any great expansion in this field. There is still a slight cushion in consumer and civilian goods which can be sacrificed in all out efforts to increase the production of military armaments. Japanese industry is almost wholly concentrated in Inner Zone areas (southern Hokkaido, central Honshu, northern Kyushu, northern Korea, southern Manchuria and Formosa). Finished munitions production is heavily concentrated in Honshu, although Manchurian industry, with help from Japan Proper, largely supports the Japanese Army in Manchuria.

5. Food. The 1944 rice consumption in the Inner Zone is higher than anticipated because of reduced wheat and barley crops. For this and other reasons, we now believe that Japanese rice reserves are uncomfortably low and that Japan must next year depend upon shipments from Indochina and Thailand for an essential portion of rice supplies. Food rations can be reduced without causing actual starvation or serious political consequences, but any reduction will result in decreased industrial efficiency and further deterioration of public health.

Appendix “C”

Military Factors

1. General. The rapid build-up and advance of Allied forces in the Central and South Pacific have brought home to Japan the realization that she must prepare to meet steadily increasing Allied strength. In addition, Japan’s relations with the U.S.S.R. are uneasy because of the ever present fear that one day that country may join the forces arrayed against her. Forced to accept the strategic defensive, Japan [Page 274] is attempting to consolidate and make secure her greatly expanded empire. She is developing successive defense lines to hold off her enemies in the hope that they, wearied by the war in Europe and perhaps divided among themselves, will attack her ineffectively or compromise to her advantage.

2. Air forces. The Japanese Air Force finds itself totally unable to match the constantly growing strength of our opposing air forces and is irrevocably committed to a strategic defensive role. Strictly offensive operations have become progressively more limited in scope and less frequent. Meanwhile, the highest priority is being given to aircraft production, and latest estimates suggest that at least 1200 combat aircraft are now being produced each month. A strenuous effort is being made to overcome qualitative inferiority by better protective armament, greater fire power, self-sealing fuel tanks, and engines of increased power. Already there has been a marked improvement in the quality of Japanese fighter aircraft. All available indications show that the combat efficiency of the Japanese Air Force is at present suffering seriously from a shortage of fully trained and experienced pilots and crews. Currently expanded facilities for individual and group training are being completed, but in periods of high attrition the Japanese will find it difficult to provide replacement of effectively trained personnel. We believe that a combination of difficulties will make it impossible for Japan’s air forces to improve materially their present qualitative inferiority so long as continued and heavy pressure is brought against her.

Although the Allies will probably meet increasingly strong numerical air resistance as they attack successive lines of defense, the scale and duration encountered at each point of attack is likely to be conditioned by Japan’s intention to preserve air strength for the final defense of those areas which she considers vital to the defense of the homeland and its critical supply lines.

3. Naval forces. Japan’s naval strength is inadequate for the defense of her outer perimeter. She is only able to concentrate portions of her fleet at a few strategic bases to parry thrusts at key points of her defense line. Allied strength is denying the Japanese Fleet the use of all but a small part of the Pacific Ocean. With her present relatively small operational fleet, Japan does not dare risk possible heavy attrition by launching any major offensives. Although she is striving to increase her fleet strength by new units, the appearance of such new ships has been so rare as to suggest difficulties in the outfitting of such forces. We believe that Japan is primarily engaged in building small escort vessels to counter the heavy toll of merchant ships taken by our submarines.

We believe that in the future the Japanese will deploy their fleet so as to be able better to meet readily the next estimated Allied blow. [Page 275] With their fleet concentrated in the Celebes Sea the Japanese had hoped to counter vigorously Allied thrusts at the Philippines. Subsequent to the battle of the eastern Philippines the main elements of the fleet were obliged to retire for reequipping and reorganization. As a result of the threat to the Bonins and the homeland, developed by our advance to the Marianas, the Japanese are likely to dispose their heavy surface units along the Kyushu–Formosa line. However, the fuel oil situation, the shipping stringency and Allied air power will have a bearing on ultimate fleet deployment.

While the Japanese Fleet suffered a heavy loss of aircraft and some carrier units in the recent battle of the eastern Philippines, Japan still retains a battle fleet of considerable power. Despite recent actions we believe that while the Japanese High Command will be cautious in the use of their battle fleet, they will continue to make vigorous efforts to oppose any Allied penetrations of the line Japan–Formosa–Luzon–Mindanao. The main considerations governing the strength, disposition, and employment of Japanese naval units opposing our advance are: local control of the air, strength of Allied forces, and the time factor. If, at any time, the Japanese should gain local control of the air, which is unlikely, we must expect heavy attacks upon our units by task forces composed of carriers, battleships, cruisers, etc. Lacking such air control or strong land-based air cover, the Japanese would use some carriers to attempt attacks on our flanks, and also light task forces might attempt night surface torpedo attacks. We can expect the Japanese to be cautious in all-out attacks on a vastly superior force, such attacks only materializing if local control of the air has been established. The element of timing will be affected by the rapidity with which the High Command reaches the conclusion that an actual occupation is threatened. In any event, our carriers will be the primary target for enemy aircraft, with our transports as secondary. Our transports will be the primary target for enemy surface forces, with our own striking forces as secondary.

4. Ground forces. Japan’s greatest armed strength lies in her large, fairly equipped and very well trained army. Because of the nature of the war in the Pacific to date, the United Nations have been unable to inflict any serious attrition on the over-all strength of the Japanese ground forces, which are as strong or stronger than in 1941.

At the present time the Japanese army ground forces total approximately 3,500,000 men. These troops are organized into about 85 divisions plus many independent units and garrisons, which have been so deployed that Japan now maintains a strong strategically defensive position. In addition, Japan has organized in Manchuria and China puppet units totaling approximately 300,000 and 400,000 men respectively. The strongest concentrations of forces are in Japan Proper, Manchuria and China. Since United Nations forces have [Page 276] begun to threaten seriously Japan’s position in the Central and Southwestern Pacific areas, Japan has accelerated her preparations for the defense of the vital East Indies and has reinforced her southern forces, particularly in the Philippines area.

The formation of puppet units has been general throughout Japanese occupied territory, but only on a large scale in Manchuria and China. Puppet troops in other areas have been formed primarily for purposes of political propaganda, and their military value to Japan has been negligible. The actual value of the Manchurian and Chinese puppet troops to Japan cannot be accurately assessed. They are only lightly equipped and, although some have been used in combat against the Chinese, the majority of them have had relatively little training. They are at present being used mainly as garrison units and for the maintenance of order in Japanese occupied territory. Because their loyalty is doubtful, it is unlikely that the Japanese would use them in a major engagement against well trained and equipped troops.

We believe that Japan intends to maintain generally the present strategic disposition of her ground forces after further substantial reinforcement of Formosa and the Philippines.

Appendix “D”

Military Intentions in Specific Areas

1. Japan Proper. As the war draws nearer to Japan, we may expect to find an increasingly large percentage of Japan’s heavy naval forces based in contiguous waters to protect the home islands and the essential transport routes between the home islands and the rest of the Inner Zone. Similarly, a large percentage of Japan’s total combat aircraft, particularly fighters, will be kept at bases in the homeland to protect against bombing of the concentrations of Japanese armaments production there. Also the formation of new divisions will be expedited and Japanese home defenses strengthened.

2. Northern Pacific. In view of the American position in the Aleutian Islands and the possibility of eventual Allied air and naval action from Soviet bases in Kamchatka and Soviet Sakhalin, Japan will continue her present policy of strengthening her defenses in the Kuriles and Japanese Sakhalin.

3. Manchuria. Japan has built up in Manchuria a large and highly developed army. It is largely sustained by Manchurian agricultural and industrial production, which is developing more rapidly than any other section of the Japanese Empire. The purpose of this army is to provide a force of sufficient strength to protect Manchuria from any Soviet threat and also to provide a striking force powerful enough to attack Siberia and the Maritime Provinces should Japan consider the [Page 277] latter course to be necessary. The Japanese High Command has abandoned hope of any German victory. Japan must appreciate that following peace with Germany, Soviet military capabilities in the Far East will increase progressively and, in fact, the initiative along the Manchurian border will eventually pass to the U.S.S.R. In view of the Soviet threat, Japan is unlikely to release any appreciable forces from Manchuria unless they can be quickly restored. She will continue to maintain a strong defensive position there, but is unlikely to undertake any offensive action unless she becomes convinced that the U.S.S.R. is about to enter the war against her.

4. China. Allied air action from China is increasingly menacing Japan’s present economic and defensive position, and the Japanese are taking stronger counter measures by the occupation and neutralization of some of the more accessible Allied bases.

The Japanese have now completed military operations between the Yangtze and Yellow Rivers and are in process of consolidating their position in this newly captured territory while reconstructing the railroad line linking Hankow with Peking. The primary objective of current operations south of the Yangtze is to deny to the Allies air bases in southeastern China. In order to accomplish this we believe that they intend to occupy the railway line between Hengyang and Kweilin and also eventually to establish overland communications between their forces in central and south China by occupation of the railroad line between Hengyang and Canton.

The Japanese have the capability of successfully carrying out these intentions. Whether or not they will commit sufficient forces for the final completion of such operations may however be influenced by the rapidly increasing threat from the Pacific. We believe that the Japanese do not intend to weaken the ground forces they now have based in China unless in due course some of these divisions are urgently required for the defense of Japan Proper or Formosa.

5. Burma. The main object of Japanese operations in Burma will be to contain large Allied forces in terrain favorable to the Japanese and to prevent the reopening of the land route to China. The Japanese will, when possible, continue to undertake limited offensive action designed to break up Allied offensive preparations and to divert as large a part as possible of the forces of the Southeast Asia Command.

6. Malaya–Sumatra. This area is of great importance to the Japanese, both for its own resources and as a barrier on the approaches to the South China Sea from the west and south. The Japanese, however, presumably consider their present strength there adequate to meet any threat likely to arise during 1944. In view of their preoccupation with more immediate threats to Japan Proper, Formosa, and the Philippines from the Pacific and by air from China, as well as the [Page 278] potential threat from Siberia, we anticipate no substantial reinforcement of Malaya–Sumatra until a threat to that area is more clearly apparent, and then only as may be warranted by the then existing over-all situation.

7. East Indies. We believe that Japan will not in any circumstances voluntarily relinquish her hold upon the East Indies, but will continue to maintain in the area the strong ground forces which already have been deployed for their defense. Although the Japanese in due time will appreciate that their sea communications to the Indies may be severed, they will consider the continued denial of the area to the United Nations forces as of such strategic importance as to warrant the sacrifice of forces stationed there.

8. Formosa–Luzon–Mindanao. Currently the Japanese are engaged in strenuous efforts to reinforce and build up ground, air and naval defenses in these areas. Allied attack upon any part of the line will be fiercely resisted by all forces immediately available, the scale and intensity of such resistance progressively increasing from the southern to the northern part of this strong eastern defense to the vital line of sea communications with the East Indies. Although Allied occupation of Mindanao would greatly increase the threat to Japan’s position, the occupation of Luzon would make the passage of shipping through the South China Sea highly precarious, while the capture of Formosa would substantially sever all sea communications to the south and in addition offer a strong base for direct assault upon Japan Proper. We believe that the Japanese intend to have deployed in the immediate future all forces which they consider can be spared for the defense of the southern Philippines, whereas land and air strength in Luzon and Formosa will continue to build up at an accelerated rate should the Allies occupy the Palaus.

9. Central Pacific. In the Bonins, at Palau, and at Halmahera local Japanese ground forces will resist to the maximum extent of their capabilities, but without strong naval and air support. The scale of naval resistance will be governed by the number of their own land-based aircraft immediately available, the strength and dispositions of our own forces, and the time at which they determine that further occupation is threatened.

  1. Submitted for consideration by the Combined Chiefs of Staff under cover of a note (not printed) by the Secretaries of the Combined Chiefs of Staff (C.C.S. 643/1) dated September 9, 1944. This report was noted by the Combined Chiefs of Staff at their 173d Meeting, September 13, 1944. See post, p. 320.
  2. Japan Proper, Korea, Manchuria, North China, Formosa, and Karafuto (Japanese Sakhalin). [Footnote in the source text.]
  3. Not printed.