In August 1945 , the Kwantung Army had declined to around 713,000 men ( from a previous total of 1,320,000 ) and was defeated by Soviet troops during the Manchurian Strategic Offensive Operation . The Kwantung Army surrendered to the Soviets the day after the Surrender of Japan and was subsequently dissolved . The Kwantung Army was responsible for many of the worst Japanese war crimes during World War II , including the sponsorship of Unit 731 which participated in biological warfare and human experimentation against civilians and prisoners of war
Unit 731
Unit 731
Kwantung Army