TAIYUAN, Feb. 12 -- A villager in north China has stumbled upon a book about the trials of Japanese biological troops during WWII, with details of atrocities in China.

Zhao Yungang in Changzhi City, Shanxi Province, told Xinhua on Wednesday he found the book accidentally at the bottom of a chest while tidying up the affairs of his grandfather.

The book of more than 600,000 Chinese characters, published in 1950, is a Chinese translation of a volume printed by a Moscow publishing house.

It details prosecutions for preparing and using bacterial weapons, of 12 Japanese officers including Otozo Yamada, last commander-in-chief of the Japanese Guandong Army in northeast China.

The trials were held in Lhabarovsk in the Soviet Union in December 1949. The book includes indictments, confessions, defense statements and verdicts, as well as photocopies of Japanese orders for preparing and using germ weapons, and transporting live humans for experiments.

According the book, Yamada confessed to judges that a large number of people were kept in the cells of Unit 731 for experiments. He told the court that the Japanese army adopted three ways of using bacterial weapons: bombs or directly spreading them by planes or on the ground.

Yamada was sentenced to 25 years in prison and released in 1956.

More than 10,000 people were killed at Unit 731 in the Chinese city of Harbin. Civilians and prisoners of war from China, the former Soviet Union, the Korean Peninsula and Mongolia fell victims to the gruesome anti-human atrocities of the Japanese.