His son, the vice admiral, Tamon YAMAGUCHI took the initiative to the second Aviation squadron in the Battle of Midway Island at the time of the World WarⅡand then, he was killed in action.
そしてその息子であり太平洋戦争においてミッドウェー海戦で第二航空戦隊を指揮し、戦死した海軍中将山口多聞。