Japan’s PM is set to become the first foreign leader to meet US President-elect Donald Trump, since the election last week.
Shinzo Abe said he wanted to “build trust” and “work together for prosperity and world peace”, before leaving for his trip.
The meeting in New York comes amid concern over the foreign policy direction of Tokyo’s biggest ally.
Mr. Trump has said Japan needs to pay more to maintain US troops on its soil.
He also condemned a major trade deal struck by President Obama with Japan and other Pacific Rim countries.
The US and Japan have been key allies since the end of World War Two, when the US helped Japan rebuild its economy.
Mr. Abe is stopping in New York on his way to an Asia-Pacific trade summit in Peru.
But details of Thursday’s meeting are unclear, with a Japanese official saying exactly where it will happen has not been firmed up.
“There has been a lot of confusion,” a Japanese official told Reuters news agency.
The BBC’s Paul Adams in Washington says Mr. Trump has toned down some of his more strident rhetoric since the election, but that hasn’t stopped observers wondering whether the fundamentals of post-war US policy on Asia can survive.
Mr. Trump has also yet to select his new cabinet and other positions. He has denied that the transition to the White House is in disarray.
Mr. Trump and Vice President-elect Mike Pence have spoken with 29 world leaders since the election, according to a statement from the transition team.
It remains unclear who else might be at the meeting with Mr. Abe.
High-level talks are rarely held in such an informal context and Tokyo is keen to minimise uncertainty during the long handover of power.