For the first time, a former high-ranking diplomat testified in court on Tuesday that secret pacts existed between Japan and the United States over the May 1972 reversion of Okinawa to Japan.

On behalf of a group of citizens seeking disclosure of three diplomatic documents related to the reversion, Mr. Bunroku Yoshino, former director of the Foreign Ministry's American Bureau, told the Tokyo District Court that the two countries concluded secret pacts under which Japan agreed to shoulder the burden of not only $16 million to move a Voice of America relay station abroad, but also $4 million that the U.S. was supposed to pay to help restore U.S. military areas to farmland.

It is hoped that his testimony will give impetus to efforts to uncover hidden aspects of diplomatic negotiations over the reversion. Until recently, the Japanese government denied the existence of secret pacts. But Mr. Yoshino testified that the initials "BY" on documents — photocopies of which were discovered in the U.S. in the early 2000s — were his.

The reversion agreement signed in June 1971 mentioned payments of $320 million by Japan. But the government's explanations to date have not included the $16 million and $4 million in question. It is believed that Japan paid more than $320 million in public money for purposes that remain unclear.

After the Democratic Party of Japan came to power in September, a team established by Foreign Minister Katsuya Okada began to unearth secret pacts between Japan and the U.S. The documents are believed to relate not only to the Okinawa reversion but also to agreements to allow U.S. ships and aircraft carrying nuclear weapons to transit through Japan, the U.S. to bring nuclear weapons into Japan during an emergency, and U.S. forces to freely use Japanese bases during a military contingency on the Korean Peninsula. The team plans to make public a report in January.

As far as the financial aspect of the Okinawa reversion is concerned, the government should employ all available means, including interviewing former Finance Ministry officials, to gain the full picture regarding secret agreements on Japanese payments related to Okinawa.