Japanese citizens, who were adopted by Chinese people during World War II, mourn for adoptive parents in front of a grave in a cemetery to memorize adoptive Chinese parents in Fangzheng county in Northeast China's Heilongjiang province, July 13, 2015. [Photo/Chinanews.com]

Nakamura Keiko, 73, knelt on the grave of her parents and wept.

"Mom and dad adopted me when I was three. They never had a child of their own and raised me as their daughter. They brought me up and sent me to school. I thank them and all Chinese for giving me a life," she said.

The delegation arrived in China only a few weeks before the 70th anniversary of the end of the wars.