Opening up Japan's politically sensitive agriculture market is the key to establishing a free-trade agreement between Japan and the United States, according to the U.S. Chamber of Commerce's vice president for Asia.

It was an agricultural concession that helped set up the U.S.-South Korean FTA that was concluded April 2, said Myron Brilliant, who was in Tokyo to attend a business symposium hosted by the Asia Society.

In an interview with The Japan Times on Thursday, Myron said that Seoul agreed to phase out its 40 percent tariff on U.S. beef over 15 years, but that its rice market was excluded from the deal.