Survivor Ma Fucheng (right) was invited to Osaka, Japan, to give evidence before a jury on May 23 last year. MA XINGHUA/XINHUA

No apology

Although 2015 marks the 70th anniversary of the end of WWII, the Japanese government has used a number of historical and legal excuses to justify its refusal to offer a formal apology to the people of Chongqing, or compensate them for the losses incurred in the air raids.

In the 1990s, Su and other survivors began campaigning for an apology and compensation, but met little success.

Pan Guoping, a law professor at the Southwest University of Political Science & Law in Chongqing who acts as a legal adviser for the group, said: "We've launched appeals in the courts in Tokyo several times over the years, but our cases were always rejected by the courts, which cited a variety of reasons,"

According to Tong Zeng, president of the China Federation to Demand Compensation from Japan, the imperial army committed a huge number of war crimes in China during WWII. To date, 30 different groups across the country have tried unsuccessfully to claim compensation.

Japan says the Chinese government waived the right to reparation by signing the Sino-Japanese Joint Communique of 1972, which sought to normalize relations between the two countries.

"Japan's excuses are rootless. Just because the Chinese government waived the right (to reparation) it doesn't mean that Chinese individuals should give up their right to seek individual compensation," Tong said.

In April, the group from Chongqing scored a minor success, when one of the cases it brought was heard in a Japanese court. "After years of struggle, and with the help of the Japan Lawyers League, our appeal was finally accepted by the Tokyo District Court. The first hearing will begin on February 25," said Lin Gang, the head lawyer representing the group from Chongqing.

On January 3, members of the Japanese Lawyers League visited Chongqing to hold meetings with the group and help the survivors prepare for the hearing in Tokyo.

"The rise of right-wing forces in Japan in recent years has made the road tougher for litigation groups from China seeking compensation. But there's also been a welcome trend of peacemaking in Japan after a group of concerned lawyers founded the Japanese Lawyers League," said Lin, who is also an associate professor of law at Southwest University of Political Science & Law.

"The league has helped the victims of Japan's WWII atrocities from different countries to collect evidence and appeal for compensation. The lawyers played a vital role in arranging for our appeal to be heard," he said.

"The chances of winning the case are very slim. But the members of the group have told me they won't give up, and neither will I."

Han Junhong contributed to the story.