A letter written by a Japanese soldier from Hiroshima to his father on January 8, 1938, has revealed further evidence of atrocities committed against civilians in Nanjing. The letter is among 13 newly released sets of historical materials made public on December 5, 2025, documenting the Nanjing Massacre, during which an estimated 300,000 Chinese civilians and unarmed soldiers were killed by Japanese forces over six weeks from December 13, 1937 to January 1938.

The release comes ahead of the 88th anniversary of the Nanjing Massacre. In 2014, China designated December 13, the day the atrocity began, as a national Memorial Day. A National Memorial Service is held in Nanjing to honor the victims.