In March 1945, 14-year-old Hideo Shimizu was conscripted as a Youth Corps member and sent to the headquarters of Japan's Unit 731 in Harbin, northeast China's Heilongjiang Province, the base where Japan planned, organized and conducted germ warfare during World War II.

After nearly 79 years, he returned to China to acknowledge the atrocities committed by the Japanese forces during the invasion and to offer his sincere repentance and apologies to the victims.

On Tuesday, Shimizu, now 94, repented and apologized in front of the monument to "apology and the commitment to peace without war" at the Unit 731 headquarters site.

Shimizu also visited the former site of Unit 731's headquarters building, including the office of the unit commander, the specimen room, and the site of the frostbite laboratory.

Jin Chengmin, curator of the exhibition hall, said that at each exhibition, Shimizu paused to think deeply before conducting a thorough on-site verification. He identified the room housing the human specimen displays as the one on the far west side of the main building, near the southern end — a conclusion that was definitively confirmed today.

Shimizu recalled that in the specimen room, he had seen a variety of dissected human organs soaked in formalin-filled bottles, and he had been ordered to collect the bones of prisoners who were used as experimental subjects.

Jin said that despite being a young soldier who served for only a short time as a support technician, Hideo Shimizu astonishingly gained extensive knowledge of the inner workings of Unit 731. This suggests that the activities of Unit 731 were likely far more widespread, or that much remains hidden from public knowledge.

In the comment section of China Media Group's news channel's Weibo post, a Chinese netizen wrote, "We need more people like him to come forward. Although forgiveness is impossible, it's essential to support those who acknowledge the truth."

Jin stated that, aside from the teenage soldiers and those who were very young at the time, almost no one else survived. Hideo Shimizu, now 94 years old, is one of the few remaining members of that Youth Corps. Given how few of these soldiers have lived to this day, it is even more remarkable that he has the courage to come forward, revisit the past, and offer apologies and remorse.

"The war ended 79 years ago, and most members of Unit 731 have passed away. Shimizu is currently the only surviving member who is willing to expose the Unit's crimes publicly, and he is likely to be the last Unit 731 member to return to Harbin," said Jin.

In the comment section of Xinhua News' Weibo post, a Chinese netizen wrote, "The 14-year-old soldier from back then is now 94. The vast majority of the Japanese invaders have taken their secrets to the grave. It's truly commendable that he dares to come forward, testify as a witness to the atrocities committed by the Japanese army, and provide us with crucial evidence!"

China's Foreign Ministry commended the courage of Shimizu for revealing the historical truth and faced it squarely, spokesperson Lin Jian said on Tuesday.

"Japan needs to heed the call for justice from both home and abroad, face up to and reflect on its history of militarist aggression, respect the feelings of the people from the victim countries in Asia, including China, draw lessons from history, get rid of the specter of militarism that still haunts it, and never let history repeat itself," Lin said.

Unit 731 was a top-secret biological and chemical warfare research base established in Harbin as the nerve center for Japanese biological warfare in China and Southeast Asia during World War II.

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.

(With input from Xinhua)