Don’t underestimate the strength of Japan’s strategic transformation, above all in its hardening determination to face accumulating threats. The shift becomes clear to anyone who engages these days with Japanese officials and defence analysts, as I discovered at the Security and Defence PLuS Joint Conference on Comprehensive Security in the Indo-Pacific, held on 14 and 17 November.

This shift is being driven in large part by the new political leadership of Prime Minister Sanae Takaichi and her mentee, Defence Minister Shinjiro Koizumi, who have pledged to accelerate defence spending.

But an even more important shift is in Japan’s strategic mindset. Tokyo is becoming more willing to call out the threat posed by Chinese aggression and to shoulder a greater share of the regional security burden. Takaichi’s recent break from strategic ambiguity, describing a conflict in the Taiwan Strait as a potential ‘existential crisis situation’ for Japan, was a case in point. It was bold statement she later softened only marginally, but by then the message had been delivered.

Expect this clarity to flow directly into Japan’s next National Security Strategy. Scheduled for release between late 2026 and early 2027, the strategy will almost certainly frame China as Japan’s central challenge and serve as the precursor to a defence–industrial expansion not seen in decades.

There are many factors behind this transformation, not least the enduring ‘Free and Open Indo-Pacific’ concept essential to Japan’s national survival. But deep vulnerabilities in energy supply, food security and maritime access in the South China Sea intensify the risks associated with a worsening security environment.

Japan has very low domestic energy production, importing around 90 percent of its supply. This includes oil, coal and liquified natural gas, of which Australia supplies a significant share.

Takaichi has signalled that building energy resilience is a top priority and intends to revive Japan’s nuclear power industry. A deal signed during US President Donald Trump’s visit outlined Japanese companies’ involvement in the development of next-generation nuclear reactors and small modular reactors. In the long-term, this could see Japan join China, France, South Korea and Russia as a leading nuclear technology exporter.

Food insecurity is also a major issue, with Japan’s food self-sufficiency rate being the lowest among the G7. Much of its grain, seafood and animal feed is imported from Southeast Asia, Australia and the United States.

This reliance on importation explains Japan’s strategic web of coast guard partnerships across the region—including with the Philippines, Vietnam, Indonesia, India and, most recently, Taiwan— designed to strengthen maritime domain awareness.

Japan’s strategic recalibration is now being matched by hard-power decisions that would have been unthinkable a decade ago. Koizumi’s 6 November comments that Japan must seriously examine the possibility of nuclear-powered submarines underscored the country’s expanding defence–industrial confidence and emerging interoperable capabilities. Alongside Japan’s role in manufacturing Australia’s next frigate class, submarines could be the next step in diversifying AUKUS production and spreading risk across trusted partners—an idea not totally out of step with Japanese thinking. As a Japanese former vice-minister of defense for international affairs told the conference, Japan should be enhancing its partnerships with both Australia and South Korea.

Taken together, these developments reflect a serious hardening of Japan’s security posture and an opening for Australia to build on its trusted partnership. A formal security alliance could see Australia and Japan complement the US and collectively protect the maritime order in the Indo-Pacific from coercion and intimidation.