A public memorial ceremony was held on Saturday for the 100,000 miners who died while being forced to work for the Japanese in Fuxin, Liaoning province, during their occupation from 1933 to 1945.
More than 1,000 people attended the ceremony.
Li Xi, Party chief of Liaoning, provincial Governor Chen Qiufa, and 83-year-old Gao Duoxian unveiled a statue for the restored and reopened memorial hall at the site of the miners' mass grave.
The statue shows a cart loaded with miners' helmets, and it carries a warning to learn from history.
"The mass graves in Fuxin truly record the monstrous crimes committed by the Japanese imperialists and are hard evidence of the Japanese invaders' persecution of Chinese miners," Li told the audience.
The Japanese army occupied Fuxin in Northeast China in 1933 and set up a mining company in 1936.
By the time Japan surrendered on Aug 15, 1945, the army had taken about 25.3 million metric tons of coal - and at least 100,000 miners had died. Up to 70,000 of those miners were buried at Sunjiawan, where the memorial hall stands.
Gao's father was a miner there. "I can never forget the day in 1944, when I was 12 years old, that my father and his two brothers were taken away forcibly by the Japanese," said Gao.
"Although they escaped from the miserable mine near the end of the war, my father could not work because of his injuries," he recalled.
Mass graves of miners have been found in Liaoyuan in Jilin, Datong in Shanxi and Huainan in Anhui, among other places. The one in Fuxin is the best preserved and the largest of its kind.
According to Zhang Baoshi, head of the memorial hall, three pits have been excavated.
"We protect the remains and maintain their original posture," said Zhang, "You can see one man was trying to climb out of the pit. It means he was still alive when he was buried."
zhangxiaomin@chinadaily.com.cn