Why Japan is fast-tracking its defence overhaul

Japanese Prime Minister Sanae Takaichi is planning to revise Japan’s three key national security documents within this year. Collectively known as the “Three Security Documents”, they comprise the National Security Strategy, the National Defense Strategy, and the Defense Buildup Program.

Together, these constitute Japan’s highest-level policy framework governing its foreign and defence policies. Looking ahead over the next five to ten years, the documents set out Japan’s assessment of its security environment, its diplomatic and defence objectives, and the fundamental principles guiding areas such as economic security and cyberspace.

A changing threat landscape

The current versions of the three documents were formulated in December 2022 under the administration of then-Prime Minister Fumio Kishida. Given that they were intended to guide the next five to ten years, there would ordinarily be no need to revise them at this stage.

However, in light of further changes in the security environment and rising defence expenditure, the Takaichi administration has concluded that revisions are necessary and aims to complete them this year. The first expert panel meeting was convened in April, and comprehensive discussions on the specific content are now underway.

To understand the significance of the revisions, it is first necessary to recognise that changes in the security environment are regarded as the fundamental justification. Russia’s invasion of Ukraine has continued for more than four years. North Korea has supported Russia’s war effort, while China has supplied Russia with dual-use goods that have helped sustain its military operations — it is evident that China is expanding its influence.

Beyond Ukraine, military conflicts have also erupted in the Middle East and elsewhere. At the same time, the widespread use of unmanned weapons systems and the growing application of artificial intelligence (AI) have rapidly transformed the nature of warfare, compelling countries to adapt.

Beyond these broader changes in the security environment, another major challenge for the Takaichi administration is the evolving US security posture. Japan must therefore reassess what it can and should do on its own, recognising that the roles expected of America’s allies and like-minded partners are also changing.

The wrong focus

What, then, are the key substantive issues? Media attention has focused on the Three Non-Nuclear Principles — Japan’s longstanding national policy of not possessing, not producing and not permitting the introduction of nuclear weapons — as well as on the transfer of defence equipment.

Indeed, Takaichi has consistently called for reconsidering the “not permitting the introduction” component of the Three Non-Nuclear Principles. Yet the Liberal Democratic Party’s recommendations on the Three Security Documents, submitted in May, made no mention of revising the principles. Instead, they called for Japan to further strengthen the credibility of US extended deterrence, centred on the US nuclear umbrella.

Meanwhile, with regard to defence equipment transfers, the Takaichi administration had already revised the Three Principles on Transfer of Defence Equipment and their implementation guidelines in April, marking a policy shift towards permitting, in principle, the export of weapons with lethal capabilities. This issue is therefore unlikely to emerge as a new focal point in the revised security documents.

The four priorities

First, Japan aims to sustain and strengthen its defence capabilities over the long term. This includes enhancing the country’s capacity to sustain military operations as a whole-of-society effort, as well as ensuring the long-term viability of the Ministry of Defence and the Self-Defense Forces. In particular, as Japan’s overall population continues to decline, ensuring sufficient personnel for the Self-Defense Forces has become an integral part of this challenge.

Second, Japan must respond to changes in the security environment, including setting new targets for defence spending. NATO members and South Korea have already clearly stated their intention to raise defence expenditure to 3.5% of gross domestic product (GDP) as soon as possible. It remains unclear what figure will ultimately be proposed in the revised Three Security Documents, but it is widely expected to exceed the current target of 2% of GDP.

Equally important is adapting to “new forms of warfare”. From unmanned systems and AI technologies to enhancing the resilience of society as a whole and strengthening the capacity to sustain prolonged military operations, these will all become major priorities. Economic security also forms part of this agenda.

Third, the revised documents will establish specific objectives for responding to the changing security environment around Japan. In recent years, Japan’s surrounding security environment has undergone dramatic changes. Chinese carrier strike groups have crossed the first island chain and are now operating between the first and second island chains.

Under these circumstances, the defence of the Second Island Chain has become increasingly important, while safeguarding the waters between the First and Second Island Chains has also emerged as a key challenge. The strategic focus is no longer confined to the East China Sea but has shifted to what can broadly be described as the Western Pacific.

Fourth, Japan seeks to strengthen and deepen cooperation with the US’s allies and other like-minded countries. This objective is closely linked to all three of the preceding priorities. Whether in maintaining maritime lines of communication, securing supply chains or enhancing the ability to sustain prolonged military operations, such cooperation will become increasingly indispensable regardless of the specific contingency envisaged.

Work on the revised Three Security Documents is under way, with the government aiming to release them by the end of the year. As the drafting process advances, their overall framework and strategic narrative are gradually being made public.

These documents will form the cornerstone of Japan’s security policy for the coming years as it seeks to respond to a rapidly changing security environment. To avoid misunderstandings, the Japanese government will need to explain the revisions clearly and prudently, not only to its domestic audience but also to the international community.

This article was first published in Lianhe Zaobao as “日本安全保障相关三份文件的修订”.

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