With U.S. President Donald Trump becoming the first state guest to visit Japan since its new imperial era Reiwa began, analysts are watching to see if he and Prime Minister Shinzo Abe can demonstrate a robust bilateral alliance without exposing any rifts over trade and North Korea.

Japan hopes Trump's four-day trip, which started Saturday, will show that the bilateral alliance is "rock solid" and that the two countries are "friends in trade despite some tough negotiations going on," says Andrew Oros, a professor of political science and international studies at Washington College in Maryland.

"Prime Minister Abe and his staff have gone to great lengths to give President Trump the 'wow factor' that he seems to delight in, including the honor of being the first foreign leader to meet with Emperor Naruhito," Oros said.

A day after entertaining Trump with a golf outing and a visit to a grand sumo tournament, Abe will hold an official meeting with him on Monday at which they are expected to focus on bilateral trade and policy toward North Korea. Trump will also have an audience that day with the emperor, who ascended to the Chrysanthemum Throne on May 1.

In addition to the state visit, the U.S. leader will travel to Japan again in late June for a Group of 20 summit in Osaka. In a meeting in April in Washington, Abe and Trump agreed to speed up negotiations for a bilateral trade deal, which the president regards as a means to cutting the U.S. trade deficit with Japan.

Analysts say the regularity of Abe-Trump meetings -- and the prime minister's embrace of the unpredictable and mercurial president -- is remarkable, and that frequent interaction shows that Tokyo and Washington attach a great deal of significance to bilateral relations.

"I believe there is a genuine human connection between Prime Minister Abe and President Trump, so they support each other," said Benjamin Self, vice president of the Maureen and Mike Mansfield Foundation, a Washington institution dedicated to supporting U.S.-Asia relations.

"That does not mean, though, that either will sacrifice their own national interest," especially when Trump is looking for major diplomatic and trade wins ahead of his 2020 re-election bid, he said.

While Abe's show of close ties with Trump "should not matter in terms of real policy concessions by the United States," Self said it may help boost Abe's Liberal Democratic Party in a House of Councillors election -- or possibly simultaneous elections with the House of Representatives -- in the summer.

That is because the close relationship with the U.S. president may matter for the Japanese public's sense of national image, as well as how the alliance is viewed by other countries such as China and North Korea, he said.

Other pundits expressed a similar view, saying Abe's embrace and flattering of Trump have little effect in curbing the U.S. leader's push to address the bilateral trade imbalance through, for example, further opening of Japan's agricultural market, a sensitive topic for Tokyo.

While maintaining hefty tariffs on steel and aluminum imports from Japan and other U.S. trading partners, Trump has also threatened Tokyo and other major car exporters with a potential 25 percent automobile levy in a bid to pressure them into making concessions as part of his "America First" trade policy.

"Trump is convinced that Japan takes advantage of the United States on trade, and it is probably impossible to change his mind," said James Schoff, a senior fellow of the Asia Program at the Carnegie Endowment for International Peace, a Washington think tank. "This is a complicating factor for near-term bilateral relations."

In a meeting Saturday, Japanese economic revitalization minister Toshimitsu Motegi and U.S. Trade Representative Robert Lighthizer were unable to find common ground in regards tariff cuts on agricultural and industrial products, making it increasingly unlikely that their leaders will make major progress toward reaching a trade agreement while Trump is in Japan.

"The Abe-Trump relationship ameliorates this problem to some degree. But if Trump is frustrated with China on trade, he might be more verbally critical of Japan during this trip," Schoff said, in reference to the tit-for-tat tariff war between Washington and Beijing.

Despite uncertainties on the trade front, Abe and Trump appear to be on the same page as to how to deal with North Korea, though the two allies showed different responses to Pyongyang's launches of short-range ballistic missiles and other projectiles earlier this month.

While Japan condemned the May 9 ballistic missile test in violation of U.N. Security Council resolutions, Trump has downplayed its significance, appearing instead to want to continue engagement with North Korean leader Kim Jong Un in hopes of holding a third summit ahead of the 2020 election.

"Trump will never admit a mistake. He has talked so positively about his relationship with Kim Jong Un and the progress they've been making since the first U.S.-North Korea summit last June in Singapore," Schoff said.

"But privately he will probably agree with Abe that it's important to keep up sanctions pressure and to maintain readiness against North Korean provocations."

Abe's offer for a first-ever Japan-North Korea summit without preconditions would fit well with Trump's desire to expand dialogue with Kim, including on the issue of Pyongyang's abduction of Japanese nationals in the 1970s and 1980s, according to Schoff.

"There is room to coordinate between Abe and Trump a policy of engagement and openness with North Korea, but one that remains principled on the need for concrete progress on denuclearization before sanctions relief," he said.