Japanese–Soviet campaigns and relations, 1939–45

Japanese–Soviet campaigns and relations, 1939–45. Japan fought two major campaigns against the USSR, in 1939 and in 1945 (see Map 59). In between, the two countries maintained an uneasy truce.

Japan's conclusion of the Anti-Comintern Pact with Nazi Germany in 1936 and its aggression the following year which started the China incident increased tension between the two countries. This precipitated a number of border disputes between the USSR, and/or Soviet-backed Outer Mongolia, and Japan-backed Manchukuo, garrisoned by the Kwantung Army, which escalated from May 1939 onwards to include Soviet bombing raids on Manchukuo, and Japanese air attacks on Mongolia which were not authorized by the Army General Staff in Tokyo, and which culminated in a Soviet offensive in August 1939. Never before had aircraft been used on such a large scale and ‘from 28 May onwards the numbers multiplied until at last 150–200 or more aircraft were engaged in a single battle’ ( A. Sella. ‘Khalkhin-Gol: The Forgotten War’, Journal of Contemporary History, 18, 1983). On 2 July Japanese infantry of the Kwantung Army crossed the River Halha into Mongolia but were stopped, as were Japanese tanks. Reinforced with artillery the Kwantung Army tried again on 23 July, but were again checked. However Stalin, concerned that the Japanese were aiming to cross into Soviet territory and cut the Trans-Siberian railway—the only means of transporting troops to and from the Far East—sent General Zhukov to reorganize Soviet forces into the newly formed First Army Group and launch a counter-offensive. Zhukov arrived in early June and began gathering a powerful force (35 infantry battalions, 20 cavalry squadrons, 500 aircraft, and 500 of the new and powerful T34 tanks) which outnumbered anything the Kwantung Army could put into the field. These preparations he carefully disguised by sending easily deciphered radio messages which indicated he was concerned only in defence (see also signals intelligence warfare), but on 20 August he launched a massive surprise offensive (known to the USSR as the Kalkhin-Gol, or River Halha, battle, and to the Japanese as the Nomonhan Incident, after the border post where the Red Army crossed into Western Manchukuo) that in ten days reached objectives 30 km. (18.6 mi.) beyond the Khalka. ‘Zhukov's essential achievement lay in combining tanks, artillery, aircraft and men in an integrated offensive for the first time in modern war. By 31 August the Russians had completed what they described as the most impeccable encirclement of an enemy army since Hannibal beat the Romans at Cannae. The 23rd Division of the Kwantung Army was virtually wiped out, and at least 18,000 Japanese were killed’ ( P. Snow, ‘Nomonhan—the Unknown Victory’, History Today, July 1990).

There was a general feeling among Japanese leaders that as long as the China Incident lasted, Japan was in no position to engage in an all-out war with the USSR. But there is no doubt that Japanese middle-grade officers in the Kwantung Army were prepared to step up the scale of fighting and were eager to strike a heavy blow at the Soviet Army.

The Nazi–Soviet Pact, signed on 23 August 1939, convinced Japanese leaders that the Soviet–Japanese balance of power had shifted against Japan. They started every effort to end hostilities through diplomatic channels. Whilst the outbreak of the European war in September 1939 convinced Moscow of the need to come to an agreement with Japan. Soviet and Japanese diplomats in Moscow arranged a cease-fire that became effective on 16 September, and agreed to the establishment of a joint committee to deal with demarcation of the border between Outer Mongolia and Manchukuo. The total killed in this first Japanese–Soviet clash reached a total of 30,000.

As Japanese military operations bogged down in China and relations with the USA deteriorated rapidly, Japan in turn hoped for an agreement with Germany and the USSR which would improve its international position. Following the signing of the Tripartite Pact in September 1940, Japan proposed a non-aggression pact with the USSR and concluded the Soviet–Japanese Neutrality Pact on 13 April 1941 in Moscow. However, the outbreak of the German–Soviet war in June 1941 forced Japanese decision-makers to reconsider Japan's relations with the USSR. A series of meetings was held to decide whether Japan should join in the attack on the USSR or stay out of the war. Foreign Minister Matsuoka Yōsuke favoured the former course, but the majority of civil and military leaders at an Imperial Conference on 2 July opted to await developments. At the same time, they decided to try to build up the Kwantung Army rapidly to facilitate an attack on the Soviet Far East Army when a favourable situation presented itself. Although the rapid build-up of the Kwantung Army continued, the Army General Staff finally decided in August not to start operations against the Soviet Army that year.

When Japan attacked the USA that December (see Pearl Harbor), Washington asked for air bases in the Soviet Far East, but Moscow refused, fearing a confrontation with Japan. Thus the Neutrality Pact remained in effect precariously through most of the Pacific war, even while Japan and the USSR were fighting desperately against each other's allies, for it shielded them both from a dreaded two-front war. With the deterioration of its military position Japan sought to remove any incentive for the USSR to enter the Pacific war. Efforts by the Japanese foreign ministry to dispatch a special envoy to Moscow to broker a peace agreement between Germany and the USSR came to nothing, as did attempts to engage the Soviets in deliberations which might improve Soviet–Japanese relations. On 5 April 1945 Moscow gave Japan formal notification of its intention not to extend the Neutrality Pact beyond its 25 April 1946 expiration date.

Unaware of the promise Stalin had made at Yalta in February 1945 (see ARGONAUT) to enter the Pacific war within three months of Germany's surrender, the Japanese government tried to obtain Soviet mediation in bringing hostilities to a close as Japanese military leaders agreed that the USSR was likely to continue to want to avoid hostilities with Japan. According to the Army General Staff estimate, the aim of the USSR would be to seek to secure a greater voice in post-war Asian affairs and would therefore prefer to have the Pacific war sufficiently prolonged to exhaust both Japan and the USA before making diplomatic moves at the final stage. On 7 August the Japanese foreign minister, Tōgō Shigenori, finally instructed Ambassador Sato Naotake in Moscow to seek an immediate audience with Foreign Minister Vyacheslav Molotov to determine the Soviets' attitude towards acting as a mediator, but the next day, at 1700 hours, Molotov informed Sato that the USSR had declared war on Japan, effective on 9 August.

In the months following the surrender of Germany in May 1945 the Soviet Army in the Far East, commanded by Marshal Vasilevsky, had been doubled from 40 to 80 divisions. By August more than a million troops, backed by 5,000 armoured vehicles, 26,000 guns and mortars, and 5,000 aircraft, were poised to attack and two hours after Sato's meeting with Molotov, just before midnight in East Asia, a massive offensive was launched against the Japanese forces in Manchukuo and in the Korean peninsula. The seizure of the Kurile Islands and southern Sakhalin also constituted part of the Soviet continental campaign. About 39% of the Soviet forces were contained in Marshal Malinovsky's Transbaikal front (army group) which struck from Mongolia while the First and Second Far Eastern fronts attacked from the north and east. Everywhere they heavily outnumbered the depleted Kwantung Army, some 267,000 strong with another 143,000 in reserve. Soviet deception plans led the Japanese into miscalculating both where the main attack would come from, and when it would be launched, and within six days the 40 Japanese divisions had been neutralized, though some troops continued to resist strongly in the north and east up to and beyond Emperor Hirohito's announcement of Japan's surrender. The overwhelming nature of the Soviet offensive caused very high casualties among the Kwantung Army. More than 80,000 were killed, while the Soviets lost 8,219 dead and 22,264 wounded.

As a result of the USSR's entry into the war and its participation in the Postsdam Declaration (see TERMINAL), Japanese leaders came to share the notion that Japan had no choice but to accept the Declaration unconditionally. In this sense, the Soviet entry into the war had a greater effect on the decision by Japanese leaders to end the Pacific war on 14 August than the dropping of atomic bombs on 6 and 9 August.

Immediately after the end of the war, more than 500,000 Japanese soldiers, officials, and other residents in Manchuria and Korea were arrested by the Soviet Army and were detained in Siberia (see GUlag).

Hatano Sumio