A former member of the Japanese germ warfare Unit 731 Youth Corps during WWII returned to China to offer apologies to the victims killed by biological weapons of Japan, a move commended by China.

"We appreciate the courage of Mr. Hideo Shimizu to expose and face the historical truth," said Lin Jian, a spokesperson for the Chinese Foreign Ministry, on Tuesday during a regular press briefing, hoping the Japanese government could reflect on the history as well. 

Shimizu, 94, arrived in Harbin, Heilongjiang Province, on Monday evening, where he recalled the scenes of dissected human organs soaked in formalin-filled bottles in the specimen room. After spending over four months in Harbin, he was ordered to collect the bones of prisoners who were used as experimental subjects.

He also retraced war crimes, including the cultivation of pathogens, human dissections, and human experiments. Shimizu fled China with the retreating Japanese forces on August 14, 1945.

"For me, overcoming many difficulties to return to China is about hoping that the Japanese authorities can face history squarely, safeguard peace, and not repeat the mistakes of war," Shimizu said.

Chinese Foreign Ministry spokesperson Lin Jian urged the Japanese government to listen "carefully" to the calls for justice, learn from history and not repeat the mistakes of history.

Unit 731 was a top-secret biological and chemical warfare research base established in Harbin by the invading Japanese forces as the nerve center for Japanese biological warfare in China and Southeast Asia during World War II. The official number shows that at least 3,000 people were used in human experiments by Unit 731, while more than 300,000 people in China were killed by Japan's biological weapons.