President Barack Obama (right) with Japanese Prime Minister Shinzo Abe (second from right) at the Michelin-starred Sukiyabashi Jiro sushi restaurant in Tokyo on Wednesday. (Reuters)

Tokyo, April 23 (Agencies): President Barack Obama today opened a four-country Asia tour aimed at reassuring allies in the region that the US remains a committed economic, military and political partner that can serve as a counterweight to China's growing influence.

The President kicked off his trip on an informal note, joining Japanese Prime Minister Shinzo Abe at a famous Tokyo sushi restaurant with hard-to-come-by reservations and a hefty price tag.

Obama and Abe greeted each other warmly outside Sukiyabashi Jiro, the underground sushi restaurant run by 88-year-old Jiro Ono.

The outing was unusually casual by Japanese standards and underscored the effort by both countries to strengthen the personal relationship between Obama and Abe.

The restaurant had its name burnished in a 2011 documentary, Jiro Dreams of Sushi, which featured owner Jiro Ono, who still presses the sushi despite turning 86 at his last birthday.

The restaurant is usually booked up months in advance. It features a set menu of 20 pieces of gem-like sushi for 30,000 yen ($290), beer and sake not included.

One Japanese television station said the choice was Obama’s. Telephone calls to the restaurant went unanswered.

Leaders of Japan, where proper etiquette is held in high regard, rarely sit down to such informal dinners with visiting leaders.

Obama will see a more formal side of Japan on Thursday when he attends a state banquet hosted by Emperor Akihito.

If Abe and Obama chit-chat too much over their sushi they might upset their host.

The bald, bespectacled Jiro is known to discourage conversation among his guests, hoping instead that they pay full attention to the flavours of his food.