WASHINGTON — Japanese Prime Minister Yoshihiko Noda, in his meeting today with President Barack Obama, is looking to reaffirm Japan’s strong alliance with the U.S. and boost his leadership credentials as his popularity flags at home.

Noda, who came to power in September and is Japan’s sixth prime minister in six years, faces huge challenges in reviving a long-slumbering economy and helping his nation recover from the worst nuclear crisis since Chernobyl.

His Oval Office meeting and working lunch with Obama, to be followed by a gala dinner hosted by Secretary of State Hillary Rodham Clinton, could offer Noda some brief relief from domestic woes. The two sides are determined to show that U.S.-Japan ties are as close as ever, particularly after the assistance the U.S. lent following the massive March 2011 earthquake and tsunami that triggered a meltdown at a nuclear plant.

The U.S. alliance with Japan, the world’s third-largest economy, is at the core of Obama’s expanded engagement in Asia — a diplomatic thrust motivated in part by a desire to counter the growing economic and military clout of strategic rival China.

The U.S. has about 50,000 troops in Japan, and both sides never tire of saying that their defense cooperation underpins regional peace and security.