Trump urges fairer trade with Japan at start of state visit

But the world's top and third-biggest economies are also thrashing out a trade deal and Trump wasted no time in lashing out at what he sees as an imbalance between the pair.

"Japan has had a substantial edge for many, many years. But that's OK, maybe that's why you like us so much," Trump told leaders from some of Japan's leading companies, including Toyota, Honda and Nissan.

After a bilateral trade deal has been signed, it will be "a little bit more fair," vowed the president.

"With this deal we hope to address the trade imbalance, remove the barriers to United States exports and ensure fairness and reciprocity in our relationship. We're getting close," said Trump.

He added: "We hope to have several further announcements soon and some very big ones over the next few months."

Some observers suspect Abe is rolling out the red carpet to present Japan as the most favourable of the countries currently engaged in trade disputes with Washington but little concrete progress is expected with elections looming for the Japanese PM.

Japanese and US officials hail as "unprecedented" the relationship between Trump and his "golf buddy" Abe, and the pair are scheduled to again find time for a round to burnish their diplomatic bromance.

Just over an hour before Trump arrived, a 5.1-magnitude earthquake rattled buildings in Tokyo, with the epicentre very close to where the leaders are due to tee off.

The official centrepiece of the trip is Trump's meeting on Monday with Japan's new Emperor Naruhito, who only ascended the Chrysanthemum Throne at the beginning of the month following his father's historic abdication for health reasons.

"With all the countries of the world, I'm the guest of honour at the biggest event that they've had in over 200 years," said Trump before his departure.

But the visual highlight is more likely to be Trump's visit on Sunday to the final day of the summer "basho" or sumo tournament where he is expected to present the trophy to the winner.

The leaders will play golf before going to the sumo and then repair with their wives to a restaurant in Tokyo's Roppongi entertainment district, where the menu features skewers of prime sirloin beef at 5,184 yen ($47) for two.

- 'Never been closer' -

Abe has just recently returned from Washington and Trump himself will be coming back to Japan in just over a month for the Group of 20 leaders' summit in the western city of Osaka.

The relationship between the former war-time foes "has never been stronger, has never been more powerful, has never been closer," Trump said.

"This is an exciting time for commerce between the two countries that we both love."

The formal diplomatic part of the trip is limited to a short bilateral meeting and a working lunch on Monday, after which the two leaders will brief the media.

They are also poised to meet families of people abducted by North Korea during the Cold War era to train Pyongyang's spies, an emotive issue in Japan that Abe has pressed Trump to raise in talks with the North's leader Kim Jong Un.

US Trade Representative Robert Lighthizer held talks with his Japanese counterpart on the sidelines of the visit but with Abe facing upper house elections in the coming months and Trump battling China, both are likely to avoid concessions.