Chai Shirong (fourth right front), head of the Fifth Branch of Northeast Anti-Japanese United Army, led his troops back to China in July 1942. He posed before the camera with the officers of the Soviet Union army who came to see him off at the China-Soviet border. [Photo exclusively provided to chinadaily.com.cn]

The Anti-Japanese Amalgamated Army of the Northeast returned to China after being trained in the Soviet Union since 1940 to support the Soviet army's march into China's northeast and fight against the Japanese Kwantung Army.

The Amalgamated Army of the Northeast decided that they needed better tactical and technical training in guerrilla warfare so they sent recruits to the Soviet Union to learn the use of light weapons, blasting, military maps and parachuting.

After the Anti-Japanese Amalgamated Army returned, they and the Soviet Far East Army co-founded 15 strategic reconnaissance squads. They were sent to the hinterland of the northeast to airports, railways, highways and barracks to collect information from Japanese military.

The Soviet Union declared war on Japan on Aug 8, 1945, and sent more than a million soldiers to China. They destroyed the main force of the Kwantung Army within a week and liberated Lvda district from Japan's 40-year-rule.

The intelligence work continued until the end of August and proved to be effective.

The photos are exclusively provided to chinadaily.com.cn by Museum of the War of Chinese People's Resistance Against Japanese Aggression and cannot be used without permission.