One old soldier is still fighting, but this time his enemy is the passing of time and fading memories as he tries to make sure that events that occurred in Nanjing 75 years ago never escape public attention.

Then a teenager, Li Gaoshan, 88, fought, and was captured by, the Japanese during the Nanjing Massacre, and he is determined that the events that took place between December 1937 and March 1938 will never fade from memory. More than 300,000 Chinese civilians and disarmed soldiers were killed.

Soldiers carry a wreath during a ceremony marking the 75th anniversary of the Nanjing Massacre on Thursday in Nanjing, capital of Jiangsu province. [Photo/Agencies]

Li, one of three soldiers still alive who survived the massacre, works as a volunteer at the memorial hall dedicated to the massacre.

He goes to the hall every Friday to share his experience with visitors.

"I have outlived many people I knew," said Li on Thursday, the massacre's 75th anniversary.

"I want to carry on and serve as a witness, since Japan's right-wingers haven't changed their attitude.

"My testimony is more powerful while I'm still alive," Li said.

Fewer than 200 survivors of the massacre are still alive, according to Zhu Chengshan, director of the memorial hall.

"At the beginning of 2011 the number was still over 300," Zhu said. Documenting their memories is important, he said.

Li was only 13 when the Japanese army overran Nanjing in 1937. He was captured but survived what was meant to be his execution when the Japanese raked the building the prisoners were being held in with machine-gun fire.

"I climbed out from a heap of bodies and then hid on the roof of the building for several days. I had no food or water."

Li went to Japan in 1996 to share his testimony and has worked for the memorial hall as a volunteer since 2004.

Authorities in Nanjing have launched a number of surveys to record for posterity the harrowing accounts of the survivors.

The first survey, conducted in 1984 and 1985, found that 1,756 survivors were still living in the city. In 1997, however, more than 400 had died.

In 2007, another survey carried out by more than 14,700 college students in 15 of the city's districts and counties gathered key testimony and evidence from 5.7 million people.

The memorial hall has collected crucial evidence of more than 4,000 documents.

"Many of the survivors have spoken recently about their experience to us," said Zhu. "As time passes, their testimonies become more urgent."

Families of survivors are helping to record their accounts of the atrocity.

Sina Weibo confirmed on Thursday that there are seven verified micro blog accounts of survivors.

One of the survivors who opened a micro blog last December, Zhou Shaohua, passed away in April, leaving his wife to continue updating their account.

Gu Xiulan, 88, visited the memorial hall in a wheelchair on Thursday, accompanied by her son and daughter.

Gu's son, Long Jinyuan, said that his mother remembers and grieves for her slaughtered relatives and murdered father every day.