The Niigata District Court ruled Tuesday that an NHK reporter was justified in refusing to reveal a news source in connection with a suit a U.S. health food company filed in the United States over the taxation of its Japanese subsidiary in 1997, it was revealed Thursday.

The refusal by the reporter, who was not identified, was in connection with a lawsuit brought by a U.S. health food company, also not identified, on the U.S. government over the taxation of its unnamed Japanese subsidiary in 1997.

It is the first judgment backing the right to protect a news source since a 1979 ruling by the Sapporo High Court.

"Reliable information (in certain situations) is provided only when there is a relationship of mutual trust (between a reporter and a source) in which the news source will never be disclosed," Judge Tsuyoshi Daiku said in handing down the ruling Tuesday.

Daiku said the refusal by the journalist to disclose the news source was justifiable under the Code of Civil Procedure. The law recognizes confidentiality when it is essential for people to carry out their duties.

The firm claimed its U.S. tax data, which the U.S. gave to Japan's tax authorities, was leaked to the press.