One year after a U.S. Navy submarine struck and sank a Japanese fisheries training ship off Hawaii, some 500 people took part in a ceremony Saturday at which a monument to commemorate the nine Japanese killed was unveiled.

The black granite stone cenotaph, with a circumference of about 3.6 meters, was built in Kaka'ako Waterfront Park in Honolulu and bears an epitaph that names all the victims and prays for peace and safety at sea.

"Our mental anguish from the accident has yet to heal, but I have been consoled by the goodwill and sincerity of many people. I truly hope there will never be another tragic accident like this," said Tatsuyoshi Mizuguchi, 49, the father of one of the four students killed in the accident.

The 499-ton Ehime Maru sank on Feb. 9, 2001, after being struck from below by the 6,080-ton nuclear sub Greeneville off Hawaii, as the sub performed a rapid-surfacing drill for civilian guests.