TOKYO - The first state visit to Japan by a US President in nearly two decades gets under way in earnest Thursday when Barack Obama is treated to the pomp and ceremony of an imperial reception.
Obama, whose arrival in Tokyo on Wednesday evening brought parts of the Japanese capital shuddering to a halt amid tight security, will be hoping to capitalise on the enthusiastic welcome he received to shore up the cross-Pacific alliance at a time of uncertainty in Asia.
The president will open his day Thursday with a welcoming ceremony at Japan's imperial palace hosted by Emperor Akihito. After talks with Japanese Prime Minister Shinzo Abe he will tour the Meiji Jingu shrine and be guest of honour at a state dinner.
But his chief task, as far as Japan is concerned, is to offer reassurances that Washington is standing by Tokyo's side, especially over a corrosive dispute with China about the ownership of disputed islands in the East China Sea.
He will also be looking to calibrate that support to avoid giving Abe carte blanche to push a revisionist view of history that upsets China and South Korea - stop two on Obama's tour and another key regional ally.
The trip will give Obama, who has met Abe briefly several times at international summits and at the White House, a chance to forge a personal connection with the Japanese premier.
"I think one important opportunity with this longer trip is to spend time getting to sit down with Abe and talk things through," said Michael Green, who framed White House East Asia strategy for President George W. Bush.
The pair kicked things off on Wednesday night with an informal dinner at a three Michelin starred sushi restaurant, renowned for the exquisite food its 88-year-old perfectionist patron serves.
In many ways, Abe is the kind of dynamic leader that Washington, frustrated by years of stagnation in Japanese politics and the economy, had longed for.
But his nationalistic impulses and ritual offerings to a shrine that counts senior war criminals among the fallen warriors it honours bring headaches for Washington, and complicate Japan's relations with China and South Korea.
Discussions on key trade partnership
Obama plans to flesh out his vision for his "rebalancing" strategy, and ease consternation in Japan about what exactly Washington and Beijing intend when they talk of a new "great power" relationship.
The two leaders are also under pressure to make progress on auto and agricultural market access issues blocking agreement on the wider Trans-Pacific Partnership (TPP) - a proposed 12 nation trade bloc.
Top negotiators from both sides have spent days seeking a breakthrough over the dispute, which will entail painful political choices which could inflame anti-free trade advocates in both Japan and the United States.
Senior US officials and business figures acknowledge progress is critical to hopes of concluding the TPP, a vital prong of Obama's Asia pivot.
While Obama hopes to concentrate on Asia policy on a trip partly making up for a cancelled visit to the region last year, he will find it tough to stick to his narrative as the Ukraine crisis deepens.
Washington is on the cusp of stiffening sanctions on Russia following the apparent failure of an agreement reached with Moscow in Geneva last week to de-escalate tensions in eastern Ukraine.
Time spent on the worst East-West clash since the Cold War as Obama travels through Asia would be an apt metaphor.
Obama's attention has repeatedly been wrenched away from the region by global crises elsewhere during his presidency, leading some Asian allies to question US endurance in the region.
His trip will also take him to South Korea, Malaysia and the Philippines. Efforts to curb North Korea's nuclear ambitions will be a key topic in Seoul, and the US leader will also offer condolences for a ferry disaster feared to have killed hundreds.