The company, A.K. Sushi, has received more than 2,000 calls in recent months from families of missing Japanese Americans, and the company says it has been in contact with some of the people.
K Sushi said it will pay a reward of up to $2 million to anyone who can provide a piece of jewelry that can be worn by an American whose remains were never recovered from the area.
A total of 5,400 American families lost contact with relatives or friends in Japan, the most since the Second World War, according to a study released by the University of California, Berkeley, in May.
A Japanese company is offering the same reward for a piece that is made of Japanese ceramic.