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Japan's strengthening military posture and new security policies

Japan is undertaking its most significant shift in defence and security policy since the Second World War. It is sharply increasing defence spending, acquiring new defence capabilities such as long-range missiles, and strengthening its alliances with the United States (with whom it has a mutual defence agreement), the UK, and other important partners in the Indo-Pacific region.

This shift is in response to what Japan sees as a deteriorating security environment in the Indo-Pacific region, with threats posed by China, North Korea and Russia. In addition, there is growing public support in Japan for it to become a bigger defence power, though significant opposition remains.

Article 9 of Japan’s constitution and the Self-Defence Forces

Japan’s post-war constitution was written by the Allied occupying administration and came into force in 1947. The constitution has never been amended. Article 9, often described as the “peace clause”, renounces war and states that land, sea and air forces will never be maintained. Despite this wording, successive governments and judgments of the Japanese Supreme Court have argued that Japan retains an inherent right to self-defence, and it is on this basis that its armed forces, the Self-Defence Forces (SDF), are constitutional.

The origins of the SDF lie in the National Police Reserve, established in 1950 by the occupying allied administration during the Korean War. This force evolved into the National Safety Forces and then the SDF in 1954. Over time, governments expanded the circumstances in which the SDF could operate. In 1992, Japan authorised deployments on United Nations peacekeeping missions. In 2015, legislation introduced under Prime Minister Shinzo Abe allowed the SDF to mobilise and use force if Japan or its allies were under attack and Japan’s survival was judged to be at risk.

Prime Minister Sanae Takaichi’s plans for revising Article 9

Prime Minister Sanae Takaichi, who took office in 2025, supports amending Article 9. Ahead of her landslide victory in snap elections held in February 2026, she pledged to further reform Japan’s security and defence policies, and stated her support for amending Article 9 to make it explicit that the SDF are constitutional.

There is currently no agreement within Ms Takaichi’s Liberal Democratic Party (LDP), nor with their Japanese Innovation Party (JIP) coalition partners on the precise form any amendment should take. Some proposals would add explicit recognition of the SDF to the constitution, while others would remove language prohibiting the maintenance of armed forces.

Amending the constitution also remains difficult because it requires support from two thirds of members in both houses of the Diet, Japan’s parliament. The LDP–JIP coalition has a two-thirds majority in the House of Representatives (lower house), but not in the House of Councillors (upper house). Any amendment supported by the Diet also requires approval in a national referendum.

Japan’s 2022 national security and defence strategies introduce significant reforms

Japan’s 2022 National Security Strategy marked a significant change in defence policy. It announced plans to acquire counter-strike capabilities (the ability to strike an opponent’s territory following an attack on Japan) and to increase defence spending from around 1% of gross domestic product (GDP) to 2% by the 2027/28 financial year.

The accompanying National Defence Strategy and Defence Buildup Program identified several priority areas for increased investment. These include long-range missiles, integrated air and missile defence, unmanned systems such as drones, cyber and space capabilities, intelligence functions and improved command structures.

Sanae Takaichi’s government plans to update all three defence documents in 2026.

In 2025, Japan established a permanent Joint Operations Command to coordinate the three branches of the SDF. In 2026, it deployed long-range missiles to the southern region of Kyushu, placing parts of mainland China within their range. The Diet also approved legislation creating a National Intelligence Bureau and National Intelligence Council to improve coordination of intelligence activities across government.

Loosening arms exports policies

Japan has gradually relaxed restrictions on arms exports. A near-total ban was eased in 2014 and further loosened in 2023 and 2024.

In April 2026, Sanae Takaichi’s government accelerated that progress significantly. It removed all export controls on non-lethal defence equipment (other than countries under UN arms embargoes) and permitted the export of lethal arms to the 17 countries it has defence equipment transfer agreements with (which includes the UK).

Increasing defence spending

Japan’s defence spending has risen steadily since 2022. According to data from the Stockholm International Peace Research Institute defence spending increased from 1.1% of GDP in 2023 to 1.4% in 2025. Defence spending in current US dollars rose from $48.1 billion in 2023 to $62.2 billion in 2025.

Trends behind Japan’s strengthening military posture

Japan’s strengthening military posture is a product of changing attitudes among its public and political leadership towards the role and capabilities of its defence forces, as well as a perception that Japan’s security interests have been threatened by developments in the Indo-Pacific region.

Public opinion

Public support for a stronger Japanese defence posture has increased significantly over recent decades, although opinion remains divided. A late 2025 survey found that 45.2% supported strengthening the SDF, compared with 49.8% who favoured maintaining current levels.

Support for constitutional reform varies by proposal. Most respondents to a 2026 survey opposed changing Article 9’s renunciation of war, whereas 60% supported explicitly recognising the SDF in the constitution.

Regional security challenges

Japan’s 2022 National Security Strategy argues that the Indo-Pacific security environment is the most severe and complex since the Second World War. It highlights China’s military expansion, its hostile maritime activities in the East and South China Seas, and growing ties with Russia; North Korea’s advancing nuclear and ballistic missile programmes; and Russia’s increased military activity near Japan, including on the disputed Northern Territories/Kuril Islands, which Russia currently controls.

Japan strengthens its international partnerships

To counter the challenges from China, North Korea and Russia that Japan has identified, Tokyo has deepened its existing alliances within the region and beyond, including with the UK.

The United States remains Japan’s most important security ally, with around 60,000 US personnel stationed in Japan. The US armed forces have upgraded their military headquarters in Japan and increased efforts to liaise with their Japanese counterparts. Tokyo has also expanded defence cooperation with Australia, South Korea and the Philippines.

Japan’s defence relations with the UK have deepened over recent decades, and particularly since 2023. Recent developments include the signing of the 2023 UK–Japan Reciprocal Access Agreement, which facilitates military deployments and exercises in each other’s countries; the Hiroshima Accord, an enhanced UK–Japan global strategic partnership; and joint participation with Italy in the Global Combat Air Programme to develop a next-generation combat aircraft (Tempest).