The United States will revise a July 31 executive order so that the effective tariff rate on most Japanese goods will be reduced, Ryosei Akazawa, Japan’s chief negotiator, said Thursday.

A more favorable method of calculation will be used in the implementation of new duties, in line with what Japan said the two sides agreed to and consistent with the method used for goods originating in the European Union.

The reversal by the United States is the first significant victory for Japan since the two countries reached a trade agreement on July 22. They have disagreed significantly about the terms of the deal, especially details about Japan's $550 billion investment pledge, and Japan has been seeking to clarify implementation of the handshake agreement.