Dai knew he had to help his country any way he could, so he created a charity called "Team Japan."
He began contacting fellow Japanese athletes and celebrities for donations, and so far he's raised $100,000.
Japan is now dealing with a nuclear crisis which is something Dai's family is already familiar with.
His grandmother survived the atomic blast in Hiroshima during World War II.
Dai believes his country will overcome these latest hurdles, with a lot of hope and help.
"I strongly believe that Japan is going to come back,"Tamesue said.
Tamesue is now reaching out to athletes in other countries for help. Anyone who wishes to donate can go to the "Team Japan" website.