Relatives of two executed Imperial Japanese Army officers sued two newspapers Monday, demanding compensation over publications that said the duo competed against each other in killing Chinese soldiers in 1937.

Three family members of the two soldiers, who were executed after the end of World War II, filed the damages suit with the Tokyo District Court against the Asahi Shimbun and the Mainichi Shimbun, demanding 12 million yen in damages for defamation.

According to the complaint, the Mainichi falsely reported in 1937 that the two second lieutenants carried out "hyakunin giri," a contest to see who would be the first to slash 100 Chinese soldiers with their swords, while on their way to Nanjing.

The Asahi Shimbun published a book in 1981 based on accounts of Chinese survivors of the Nanjing Massacre that mentions the killing contest by the two officers during the early part of what is known in Japan as the second Sino-Japanese War, the complaint said.

The families said the Mainichi has not run a correction of its stories. The Asahi continues to publish the book even though it has been proven that hyakunin giri did not take place, the relatives claimed, saying they filed the suit because they could no longer tolerate the defamation.

The two newspaper companies said they will consider how to handle the matter after carefully reading the complaint.