This article is a snap insight into Japan’s defence posture since Prime Minister (PM) Sanae Takaichi from the Liberal Democratic Party (LDP) took office on 21 October 2025, and the implications for regional security in East Asia.

A staunch conservative, Takaichi has long argued for a tougher stance towards China. While she had expressed to Chinese leader Xi Jinping at the sidelines of the November 2025 Asia-Pacific Economic Cooperation (APEC) summit her willingness to engage in dialogue (Dominguez and Ninivaggi, 2025), Takaichi also angered China by discussing the prospect of enhanced Japan-Taiwan cooperation with Taiwanese presidential adviser Lin Hsin-i at the sidelines of the same summit (Wagatsuma, Lee and Mayger, 2025). Takaichi’s bold move to engage Taiwan, much to China’s chagrin, aligns with Japan’s own national security interests to ensure Taiwan’s de facto independence, but also risks provoking China to the extent that other security issues in the South China Sea become harder to resolve (Dominguez, 2025).

Japan, under Takaichi, is also pursuing greater military buildup. Japan now aims to increase defence spending to 2% of its gross domestic product (GDP) by March 2026, two years ahead of the original schedule (Yamazaki, 2025). Japanese Defence Minister Shinjiro Koizumi further left open the possibility of future defence spending hikes, without providing specifics; this aligns with Takaichi’s push to revise three 2022 strategy documents in preparation for increased defence spending (Johnson and Dominguez, 2025). The Takaichi government also plans to enhance the competitiveness of Japan’s defence production base by rolling back restrictions on lethal weapons exports and building weapons factories (Gale and Negishi, 2025). Finally, Koizumi has emphasised that all options, including nuclear-powered submarines, are being considered (Japan Today, 2025). The government’s multi-pronged approach signals its serious intent to transform Japan’s defence capabilities in response to an increasingly volatile security environment.

To achieve its goals, the Takaichi government is seeking collaboration with key allies, especially the United States (US). Takaichi and US President Donald Trump both favour a stronger military buildup and hawkish stance towards China, creating a strategic alliance borne from mutual need (Montgomery and Klein, 2025). The US benefits from having an Asia-Pacific ally willing to take a harder line against China (Montgomery and Klein, 2025). Meanwhile, Japan benefits from deepened defence-industrial cooperation with the US (Johnson and Dominguez, 2025). Recent talks between Koizumi and US Defense Secretary Pete Hegseth regarding the construction of South Korean nuclear-powered submarines in US shipyards suggest the possibility that Japan might acquire nuclear-powered submarine capabilities from the US in the future (Johnson, 2025). Besides bilateral cooperation, Japan has also committed to multilateral defence cooperation through the “Squad”, which consists of Japan, the US, Australia and the Philippines. At the recent “Squad” talks in November 2025, the four countries emphasised strengthened deterrence and response capabilities in the Asia-Pacific region (Johnson, 2025).

However, to achieve its goals, the Takaichi government also has the challenging task of garnering domestic support from opposition parties with divergent views. While the LDP’s new coalition partner, the conservative Japan Innovation Party (JIP), supports Takaichi’s hawkish goals, the LDP-JIP coalition does not have a majority in the Japanese Diet (Montgomery and Klein, 2025). Opposition parties might (a) view military buildup as a violation of Japan’s pacifist Constitution; (b) argue for a more diplomatic approach towards China; or (c) prioritise using available budget to ease cost-of-living pressures (Kamata, 2025; Corben, 2025). 

If the Takaichi government achieves its defence goals, tensions between China and Washington’s staunch allies could further increase. In particular, Japan’s pursuit of military buildup and equipment export - especially navy capabilities - to other countries in the Asia-Pacific could provoke escalation in the South China Sea, making a diplomatic resolution increasingly difficult to attain.