An expert committee under the Japanese government concluded last week that the country must be able to use its missile interceptors to shoot down ballistic missiles aimed at the United States.
The Yomiuri daily cited government sources as saying that the joint exercise "aims to improve cooperation between the Self-Defense Forces and U.S. forces, which is essential for missile defense."
The site of the exercise may be the Sea of Japan using the scenario of a missile attack by North Korea, the paper said.
North Korea became one of Tokyo's biggest security worries after it test-fired a long-range ballistic missile over Japan in 1998, prompting Tokyo to begin researching missile defense.
Japan's determination to boost its missile defenses was strengthened after Pyongyang conducted a series of ballistic missile tests in July 2006, and an underground nuclear test explosion three months later.
Earlier this year Shinzo Abe, who has been vying for stronger military ties with the Pentagon since his election as premier in September 2006, used his Liberal Democratic Party's parliamentary majority to push for a national referendum on the broader use of the Japanese military.
The pervading view in Japan's leadership is that outdated legislation hampers its cooperation with its ally the United States on a joint ballistic missile defense program, because the country is limited to cooperating in the early detection of potential missile launches by "rogue states" - in particular North Korea - but is unable to shoot down missiles.
During the exercise, the Maritime Self-Defense Force (MSDF) will deploy one of its five Aegis-equipped destroyer vessels, Kongo, which will team with U.S. Navy Aegis-equipped vessels that have SM-3 capabilities.
The U.S. SM-3 interceptor missiles are designed to intercept incoming ballistic missiles in mid-trajectory at altitudes up to 300 kilometers (about 190 miles).
"The exercise, which will be the practical start of the Japan-U.S. missile defense system, will be held after the Kongo holds its first test-fire exercises off Hawaii in December," the paper said.
By 2011, Japan plans to deploy a two-tier missile shield combining sea and land-based systems.
The land-based part of the shield comprises the U.S. Patriot PAC-3 systems, which will be deployed at four ground-to-air missile units and set to shoot down missiles before they hit the ground.
Under a December 2004 missile defense cooperation arrangement with the U.S., Japan deployed a high-resolution radar last year that can detect incoming missiles at the Air Self-Defense Force's Shariki base in Tsugaru, about 360 miles northeast of Tokyo.
