The Watergate scandal forced a U.S. president to resign and turned two journalists into national heroes, but a diplomatic scandal in Japan involving a secret pact with the United States over the 1972 reversion of Okinawa resulted in the convictions of the journalist who reported it and his "Deep Throat" source.

Takichi Nishiyama, a former political reporter at the Mainichi Shimbun, has broken a 30-year silence to clear his name, backed by U.S. government documents released in 2000 and 2002 that back his report on how Japan secretly shouldered $4 million in social costs for Okinawa's reversion to Japanese sovereignty from the U.S.

"The existence of the secret deal has been proved three times — first by my report and again by the two U.S. documents. However, the Japanese government has continuously denied it," Nishiyama, 73, said.