The State Archives Administration on Sunday published the confession of a Japanese war criminal, who participated in Japan's invasion of China from 1940 to 1945.

In the sixth of a series of 31 handwritten confessions from Japanese war criminals published online, Sadakichi Yamaguchi, born in Chiba Prefecture, Japan in 1920 confessed how he raped Chinese women and killed Chinese civilians.

In the 1954 confession he detailed how he and a friend raped a 30-year-old woman in Shandong Province in October 1942.

He recounted that in February 1943, he saw a soldier named Matsui "hack a Chinese woman to death from overhead" and then stabbed her crying child to death also in Shandong Province.

When entering a civilian house, he "saw Sergeant Matsui, commander of the third squad, and private first class Otani inserting a stick into the vagina of a woman aged about 40." "When I heard Otani say the longer, the better, I gave him a shoulder pole, and he exerted himself to insert the pole into the woman's vagina, brutally killing her," said the confession.

He also confessed that in September 1944, he "bloated" a Chinese peasant aged about 35 in Tai'an county "with cold water." The peasant died two days afterwards.

A total of 31 confessions, one each day, from Japanese war criminals are being published online in the run up to commemorations of the end of the war on Sept. 3.

The handwritten confessions, translations and abstracts in both Chinese and English, are published on the website of the State Archives Administration.

The confessions, which have never been released before, detail crimes perpetrated by the Japanese, including killing, enslavement and poisoning of Chinese people, as well as the use of biological and chemical weapons on live human subjects.