Proof of Japan's infamous Unit 526 unearthed in bookstore

A post-90s man has collected thousands of historical photos related to Japan's invasion during World War II, of which at least 2,000 have never been seen before.

Some Japanese soldiers in the photos are said to be from Unit 526 and "chemical troops". The pictures are among hundreds discovered in an old bookstore in Japan by Zou Dehuai's Japanese friend and then posted to China.

Unit 526 was a biological and chemical unit of the Japanese Army. In 1991, two veterans who served in the unit first revealed the hidden truth of its role. Its very existence has been controversial due to a lack of evidence with detailed proof mostly destroyed before Japan's surrender.

According to the photo album, the owner, then 21, joined the Japanese army on March 27, 1944. In the same year he was assigned to Unit 526 in Qiqihar, Northeast China's Heilongjiang province. No signs of experiments involving biological weapons are directly visible in the photos however they prove the existence of Unit 526.

Since the 1950s a large number of chemical weapons have been found in Qiqihar. Four barrels of a toxic agent were discovered on August 4, 2003 which killed or injured 43 people.

In another album collected by Zou, a photo shows bodies of Chinese children piled up. The caption claims the children were abandoned by their families despite allegations that the Japanese Army were involved in the mass slaughter of innocent Chinese citizens, including children, just for fun, during World War II.

Another photo shows a smiling Japanese soldier holding the head of a man while behind him stands another soldier, sword in hand.

Zou, who has a degree in visual communication, is interested in history and has been collecting photos from the war. He tried to verify every one in his collection.

He hopes that the evidence he has collected will be known to the world and make unbearable memories raise an alarm to later generations.

"When I got lost in Japan, local people always helped me warmly," Zou said, "I believe that as long as the Japanese government lead the public to face up to wartime history, China-Japan relations would open a new page with deep communications".