President Obama is in Asia for a four-country tour to promote commerce and trade as part of his administration's so-called "Asia pivot." But with rising tensions in the region, what does his relationship with Japan, South Korea and China look like? (Julie Percha/The Washington Post)

President Obama started his week-long tour of Asia by conducting serious policy discussions with Japan’s prime minister as well as delivering ceremonial greetings to the Japanese royal family, emphasizing the significance of the ties between the two nations.

Speaking at a bilateral meeting in the Akasaka Palace, an elegant edifice built in a European style, the president described the U.S.-Japan alliance as “the foundation not only for our security in the Asia Pacific region but also for the region as a whole.”

“We are looking at a whole range of issues that are challenging at this time, including the threats posed by North Korea and the nuclearization that has been taking place in that country,” Obama said, adding that the two countries’ “shared democratic values” will help them as they “try to make sure we are creating a strong set of rules that govern the international order.”

Japanese Prime Minister Shinzo Abe, for his part, said the fact that Obama was making a state visit to Japan showed that the president was committed to making Asia a top priority in U.S. foreign policy.

“This greatly contributes to regional peace and prosperity, and Japan strongly supports and also certainly welcomes this,” Abe said. “My administration intends to continue to contribute to regional peace and prosperity more proactively than ever.”

Before arriving in the country, Obama told the Yomiuri Shimbun newspaper that the defense treaty the United States has with Japan applies to a dispute between Japan and China in the East China Sea over a set of islands. In a written response to the newspaper, he said the United States opposes “unilateral attempts to undermine Japan’s administration of these islands.”

On Wednesday, right after Obama’s arrival in Tokyo, the president and Abe dined together at Sukiyabashi Jiro, one of the finest sushi restaurants in the world, along with the U.S. Ambassador to Japan Caroline Kennedy and National Security Adviser Susan Rice. The restaurant’s owner and sushi master, Jiro Ono, was featured in David Gelb’s 2011 documentary, “Jiro Dreams of Sushi.”

“That’s some good sushi right there,” Obama remarked as he emerged from the restaurant after the hour-and-a-half dinner with the prime minister.

The president met with Emperor Akihito and Empress Michiko at the Imperial Palace on Thursday before conducting private talks with Abe. During the meeting with Akihito, Obama noted the last time the two of them had been together he did not have any gray hair.

“You have a very hard job,” the emperor replied.