Japanese Prime Minister Sanae Takaichi’s visit to Vietnam and Australia over the past few days had all the trappings of a standard diplomatic tour. She showered her hosts with praise and gifts, including prized Japanese melons. She snapped selfies with students in Canberra and tried her hand at playing traditional drums in Hanoi.

But by the time Ms Takaichi departed the Australian capital on May 5, it was clear that the trip had been far from routine. It was the opening pitch for Japan as a force for stability and strength in a region increasingly rattled by China’s aggressive posturing and US President Donald Trump’s volatile foreign policy.

Under Ms Takaichi, Japan has pledged US$10 billion (S$12.7 billion) to help South-east Asian nations cope with soaring oil prices because of the Iran war. She has reversed long-standing limits on the sale of Japan-made weapons overseas and doubled down on shuttle diplomacy, dispatching 10 top officials abroad this week to make the case for Japan as the partner of choice in Asia.

“Japan will play an even more proactive role than ever before in building an international order based on freedom, openness, diversity, inclusiveness and the rule of law,” Ms Takaichi told students and staff at Vietnam National University in Hanoi on May 2.

Ms Takaichi, a conservative lawmaker who last fall became the first woman to serve as Japan’s prime minister, is attempting to elevate her country’s profile at a time when China’s economic and military clout is rapidly rising.

She is also navigating the unpredictability of Mr Trump, whose handling of the war in Iran has sown fears about American commitments in Asia. Japan depends on the United States, its main ally, for security. Unlike the leaders of Canada and some European countries, who have sought distance from Mr Trump, Ms Takaichi has made a point of cultivating warm ties with Mr Trump.