But he made no pledges about the Okinawa base row that brought down his predecessor.

BBC: Naoto Kan becomes Japan's new prime minister

With the base row over, if America can rely upon Japan to play a greater part in its own defence, America can reduce the number of its own troops in Japan and move some forces to Guam or even Hawaii.

ECONOMIST: Japan and America

Two soldiers were gunned down by a rogue Afghan soldier with a "personal grievance" after a row at the gates of their base, an inquest has heard.

BBC: England

US-Japan ties were strained somewhat under the previous Japanese Democratic Party (DPJ) administration amid a row over the relocation of a US military base in Okinawa.

BBC: Obama and Shinzo Abe affirm US-Japan security alliance

They helped doom Mr Hatoyama, when he stumbled into a fruitless row with America over the relocation of a marine base in the Japanese island of Okinawa.

ECONOMIST: Japan's upper-house elections