Yahoo Japan Corp. will not appeal a court ruling ordering it to identify a person who posted an allegedly slanderous message on a Yahoo Internet bulletin board, company sources said Monday.

As a result, the nation's top portal was set to disclose on Tuesday the Internet protocol address and other data on the person. The message, posted in February 2002, targeted the operator of the nationwide Kinshi Eye Clinic, the sources said.

The clinic filed suit with the Tokyo District Court, claiming the message was defamatory. It demanded that the person's name, address and other information be disclosed.

In the course of the legal action, the name and postal and e-mail addresses of the message's author surfaced, revealing that the person was from a rival medical firm.

However, the plaintiff came to doubt that the message was posted by the rival, and called for disclosure of the originator's IP address, knowing this would help identify the computer used.

On March 31, the court sided with the plaintiff and ordered Yahoo Japan to disclose the information.