In 1967, then Prime Minister Eisaku Sato declared Japan's three-point nonnuclear principle of not "producing," not "possessing" and not allowing the "bringing in" of nuclear weapons. The third point has been interpreted to mean that Japan will not allow either the stationing or transiting of nuclear weapons on its territory.
But in recent media interviews, Mr. Ryohei Murata, who served as vice minister of the Foreign Ministry from 1987 to 1989, admitted the existence of a secret pact between Japan and the United States under which Tokyo would tacitly approve the stopover of U.S. military ships or aircraft carrying nuclear weapons in Japan and their transit through Japanese territorial waters. The pact was agreed on when Japan and the U.S. revised the bilateral security treaty in 1960. He also said that he would speak in the Diet if summoned.
The security treaty says that the U.S. will hold "prior consultations" with Japan when it makes major changes in the deployment and equipment of the U.S. forces in Japan and when it uses Japanese bases for military operations outside Japan that are not related to the defense of Japan.