As the Kwantung Army 's fighting power diminished , it had to amend its operational plans against the Soviets accordingly . While the strategy for 1942 was the same as it had been in 1941 , by 1943 this had been abandoned in favor of only one attack – either on the Eastern Front against Primorye or in the north against Blagoveshchensk – which itself soon gave way to a holding action on all fronts , attempting to check the Red Army at the borders . As the Kwantung Army continued to weaken , it became apparent that even this would be too much , and so a final operational plan was adopted on 30 May 1945 in which the IJA would only delay the Soviet advance in the border zones while beginning a fighting retreat to fortifications near the Korean border , centered around the city of Tonghua – a move that , in effect , surrendered the majority of Manchuria to the opponent as a matter of course . Although by August 1945 Kwantung Army manpower had been boosted to 714,000 in 24 divisions and 12 brigades thanks to the exhaustion of local reserves , cannibalization of guards units and transfers from China , privately its officers and men were in despair . Most of the new formations , staffed by the old , the infirm , civil servants , colonists , and students were at barely 15 % combat effectiveness and heavily lacking in weapons ; out of 230 serviceable combat planes , only 55 could be considered modern . It was even briefly recommended that Army Headquarters be pre-emptively evacuated from Changchun , but this was rejected on security , political , and psychological grounds . After the war , colonel Saburo Hayashi admitted : " We wanted to provide a show of force . If the Russians only knew the weakness of our preparations in Manchuria , they were bound to attack us . " Simultaneously , Japanese intelligence watched helplessly as Soviet strength opposite them began to soar : honoring his promise at Yalta to enter the war in the Pacific within three months of Germany 's defeat , Joseph Stalin ordered the transfer from Europe to the Far East of some 403,355 crack troops , along with 2,119 tanks and assault guns , 7,137 guns and mortars , 17,374 trucks , and 36,280 horses . These men and their commanders were specially picked because of past experience dealing with certain types of terrain and opposition during the war with Germany that would be beneficial for the approaching campaign . By the beginning of August the IJA pegged Red Army forces in Siberia at 1,600,000 , with 4,500 tanks and 6,500 aircraft in 47 division-equivalents ; the actual totals were 1,577,725 , 3,704 , and 3,446 , respectively . The Soviets were very deliberate in their preparations : because operations could only last eight weeks owing to the tenuous supply situation , it was determined that only an all-axes surprise offensive would be sufficient to surround the Kwantung Army before it had a chance to withdraw into the depths of China or Korea . Aware that the Japanese knew the limited capacity of the Trans-Siberian Railway would mean that preparations for an attack would not be ready until autumn and that weather conditions would also be rather unfavorable before that time , Soviet planners enlisted the help of the Allies to deliver additional supplies to facilitate an earlier offensive . Because of this , the Japanese were caught unprepared when the Soviets attacked in August . Despite the impending catastrophe facing Japan on all fronts , the Kwantung Army commander , General Yamada , and his top leadership , continued to live ' in a fool 's paradise . ' Even after the obliteration of Hiroshima on 6 August , there was no sense of crisis and special war games ( expected to last for five days and attended by a number of high-ranking officers ) were conducted near the borders , while Yamada flew to Dairen to dedicate a shrine . Therefore , Army Headquarters was taken by complete surprise when the Soviets launched their general offensive at midnight on August 8/9 1945 . Although the Japanese offered vicious resistance when they were allowed to stand and fight , such as at Mutanchiang , almost without exception they were overwhelmed and pushed back from the front . After just about a week of combat , reacting to the Soviet declaration of war and the destruction of Nagasaki by a second atomic bomb , Emperor Hirohito overrode his military and ordered the capitulation of Japan to the Allied nations in accordance with the Potsdam Declaration . After some clarifications and a second rescript reaffirming Japan 's surrender , General Yamada and his staff abandoned the plan to withdraw to Tonghua , even though his command was still mostly intact ; the Kwantung Army officially laid down its arms on 17 August 1945 with some sporadic clashes persisting until the end of the month . The final casualties on both sides numbered 12,031 killed and 24,425 wounded for the Soviets and 21,389 killed and about 20,000 wounded for the Japanese . In the end , as Foreign Minister Shigemitsu signed the unconditional surrender of Japan aboard USS '' Missouri '' in Tokyo Bay , the men of the vaunted '' Kantogun , '' having once dreamed of riding into Siberia as conquerors , instead found themselves trudging there as prisoners of war
Yalta
Yalta Conference
Kantokuen