China's State Archives Administration plans to release videos documenting the suffering of sex slaves at the hands of the Japanese military over 70 years ago.

The eight-part video series is being released on the SAA's website, one per day, beginning exactly 70 years after then-emperor Hirohito announced Japan's surrender on Aug 15, 1945.

Japan invaded northeastern China in September 1931, with a full-scale invasion on July 7, 1937. About 35 million Chinese soldiers and civilians were killed or injured in the war that followed.

An estimated 200,000 women, euphemistically known as "comfort women", were forced into sexual slavery by Japanese troops.

Only a handful are still alive, and few have publicly admitted to having been enslaved. Thousands took their secrets to the grave without receiving any apology or compensation from Japan.

"These horrific, institutionalized acts of violence committed by Japanese invaders, rarely seen in the history of human civilization, constitute state crimes and a gross violation of the human rights of the victimized women. They are some of the most painful chapters in the annals of history," the SAA said in a preface to the video archives.

Japanese Prime Minister Shinzo Abe's statement on Friday to mark the 70th anniversary of the end of World War II made no direct reference to the "comfort women".

The first in the video series quotes Japanese war criminal Ebato Tsuyoshi as saying that a woman was forced to become the comfort woman of a Japanese sergeant during the invasion of the Shandong peninsula.

The sergeant killed her when food became scarce and ate her flesh, which he shared with his squadron after telling them that it was regular meat from their battalion headquarters, Tsuyoshi said.