Photo released on Aug 29, 2015 by the State Archives Administration of China on its website shows the image of Japanese war criminal Masao Kanazawa. [Photo/Xinhua]

BEIJING - A Japanese World War II soldier killed Chinese citizens through fiendish methods of torture that included shoving a sweet potato up a woman's vagina, according to his confession published by the State Archives Administration on Saturday.

Masao Kanazawa was stationed in Shandong province from 1943 until his capture in August 1945.

Kanazawa confessed how he broke into a house in Rizhao county and "forced an old woman aged around 60 who was sick in bed to bare her bottom".

"I stuck a whole sweet potato about six cm in diameter and 20 cm in length into her vulva, and she finally bled to death."

In another incident, Kanazawa force-fed an arrested peasant a large amount of water. "When his belly was bulging, I stepped on it. He lost consciousness and was dead within an hour."

In May 1945, Kanazawa gave instructions to "capture a man aged around 50" in Mengyin county. He forced the man to step on land mines, which seriously wounded the captive. Kanazawa then covered him in burning hay and burned him to death, he confessed.

His war crimes were not limited to torture and murder. Kanazawa admitted to gang-raping a Chinese woman along with three companions, and to sexually assaulting another woman.