Executive Summary

Anchored historically by its post-WWII pacifist constitution, particularly Article 9, Japan has long avoided projecting significant military power abroad. Historically, the nation has capped its defence spending at ~ 1% of GDP (approximately ¥5 trillion). However, Japan is undergoing a fundamental transformation of its defence posture amid intensifying security challenges in the Indo-Pacific region, and defence spending and costs for fiscal 2025 are expected to total ¥9.9 trillion ($70 billion), equivalent to 1.8% of GDP. Such challenges include increasing threats from China, North Korea, and doubts about sustained U.S. capacity-building support have pushed Japan’s defence strategy to adopt a more assertive stance. 

Key Points

Strategic Shift in Defence Posture

Japan’s National Security Strategy now explicitly calls for strengthening its “deterrence and response capacity”. It has launched a new Joint Operations Command tasked with coordinating and unifying operations across all three branches.

• Technological Advancements

Japan is developing a range of advanced weapons systems, including upgraded Type-12 surface-to- ship missiles , long-range precision-guided missiles, and hypersonic glide vehicles under a ¥32 Billion contract with Mitsubishi Heavy Industries. 

• Changing Regional Expectations and Declining U.S. Role

Recent Trump administration cuts to U.S. capacity-building programmes in Southeast Asia have left a vacuum, particularly as USAID funding has been significantly reduced. Analysts argue that Japan and Australia are well-positioned actors in the region to fill this gap and must step up to support autonomous defence capacities among regional partners.

Analysis

Japan’s strategic redirection reflects both external and internal pressure to evolve from a passive post-war security actor into an active regional defence stakeholder. The Indo-Pacific region has become an area of increased power competition, marked by intensifying territorial disputes, great-power competition, and an uptick in grey-zone scenarios such as cyberattacks. In this increasingly volatile environment, Japan can no longer rely solely on protection from the U.S. Foreign Minister Yoshimasa Hayashi recently described the current environment as “the most severe and complicated security situation since the end of World War Two”- an assertion reflecting Japan’s wider stance that strategic autonomy must be developed alongside its traditional alliance-based security posture. 

A central component in Japan’s defence restructuring is the formation of a Joint Operations Command, which aims to unify Japan’s operations across over 220,000 personnel in order to better manage everything from overseas missions to missile defense systems, and coordinates the Maritime, Ground, and Air Self-Defence Forces. Unlike previous configurations which saw each branch operate independently, this new command is designed to facilitate rapid responses to increasingly complex threats, including ballistic missile attacks and overseas missions, with greater speed and coherence. 

Additionally, Japan’s investment in advanced military technologies further illustrates its changing defence orientation. Through contracts such as the ¥32 billion agreement with Mitsubishi Heavy Industries, Japan is prioritising the development of cutting-edge weaponry, including long-range missiles and hypersonic glide vehicles. These investments are intended not only to modernise the defence infrastructure but also to support a military-industrial base capably of sustaining long-term strategic autonomy. The development and public display of advanced weapon systems not only enhances deterrence but reshapes public perception surrounding military readiness and export potential. On May 21, Japan’s largest-ever defence exhibition showcased a range of new defence technologies including railguns and high-powered lasers. The wider implications for this event suggest a growing political and industrial openness to international defence collaboration and exports. Such displays are as much about signalling deterrent capabilities as they are about shaping domestic and international perceptions of Japan’s defence identity. 

This strategic evolution is mirrored by Japan’s expanding regional role. As U.S. engagement in the Indo-Pacific recedes, Japan and Australia are emerging as critical democratic security partners, supporting a more distributed security architecture less dependent on U.S. presence. However, this transformation is fraught with tension as domestically, reinterpretations of Article 9 remain controversial. Though the constitution remains formally unchanged, successive governments have gradually expanded the scope of Self-Defense Forces (SDF) activities. Former Prime Minister Shinzo Abe championed constitutional revision to legitimise the SDF – a move criticised by some as eroding Japan’s pacifist principles. Regionally, constitutional revision risks inflaming historical sensitivities, particularly in China and the Koreas – countries which view Japanese remilitarisation through the lens of unresolved wartime legacies. Therefore, any moves to expand Japan’s defensive positioning requires careful diplomatic framing.

Ultimately, Japan is moving from post-war pacifism toward a more assertive security stance shaped by shifting regional alliances and evolving threats. If handled with strategic clarity and diplomatic tact, this transition could reposition the nation as a pillar of regional stability. However, this evolution risks inflaming already existing tensions with China, upsetting neighbouring nations wary of Japanese militarism, and dividing domestic public opinion.

Policy Implications

1. Regional Security Dynamics

Japan’s evolving posture may act as a stabilising force in the face of security challenges in the Indo-Pacific region, but could also heighten military competition, particularly with China and North Korea.

2. Alliance Expectations and Burden-Sharing

With the U.S. potentially reducing its military footprint in Japan, Tokyo’s enhanced capabilities are likely to be viewed positively by Washington as a form of burden-sharing. However, as Japan’s defence strategy changes, it faces scrutiny from neighbours with historical grievances, requiring diplomatic tact to minimise backlash from other Asian allies.

3. Legal and Domestic Tensions

While the government pushes forward with increased defence expenditure, the reinterpretation of Article 9 remains a sensitive issue domestically. The balance between constitutional pacifism and strategic necessity is looking to remain a key domestic debate in Japan.