Boston's Ropes & Gray is trying to tap into the lucrative intellectual-property and private equity business in Asia by opening a law office this fall in Tokyo.

The four-attorney office, the firm's first overseas, will serve both Japanese and American clients, as well as others trying to take advantage of the booming economies in Asian countries.

Two Japanese attorneys from Ropes & Gray's New York office will be among those starting up the Toyko office, the firm said yesterday.

James DeGraw, a parter at Ropes & Gray, said he's visited Tokyo and is currently taking Japanese language courses before his own transfer there this October.

Ropes & Gray already represents Japanese clients on patent and other intellectual-property issues in the U.S. One client recently asked if it could have a closer relationship with Ropes in Japan - and the idea was born for a new office, said DeGraw.

"They're trying to protect their patents and market share for their products," said DeGraw of Japanese clients in general.

But intellectual-property law isn't the only area of interest for the giant Boston law firm.

Private-equity companies, such as Bain Capital, are increasingly doing business and making deals in Asia, DeGraw said. Bain is a major client of Ropes & Gray, he said.

Other law firms have been setting up operations in Japan. Recently, Boston's Bingham law firm opened a Tokyo office.

By this fall, Bingham's Tokyo office hopes to expand with the hiring of more than 50 Japanese lawyers, according to the company's Web site.