When Masashi Yamaguchi's mother threw her wedding ring into the sea, he believes it was so she could remain strong and move on without her dead husband.
Yamaguchi's father, Masakazu, was one of the 28 Japanese citizens on Korean Airlines flight 007 when it was shot down by a Soviet fighter jet on Sept. 1, 1983, near Russia's Sakhalin Island, killing all 269 passengers and crew members on board.
Four decades after the incident, Yamaguchi, 42, still regrets not being able to fully repay the debt of gratitude he has for his now-deceased mother, who raised him and his two sisters on her own following the tragedy.