Japan weighs US$500 billion defence spending plan: sources

Japan’s government and ruling coalition are considering a defence build-up worth 70 trillion to 80 trillion yen over five years beginning in April 2027. That equals about US$457 billion to US$508 billion. The plan is part of Prime Minister Sanae Takaichi’s effort to strengthen Japan’s military capabilities. It matters because it would represent a major expansion of national defence spending.

The proposed money could support large numbers of drones and other equipment. Japan is also developing domestically manufactured long-range missiles. Its defence ministry is prioritising drones, artificial intelligence and space technologies. These areas reflect changing methods of warfare and the need to respond to long-range attacks.

The figure is not final. The government will compile the budget toward the end of the year and revise three security-related documents. Coalition partners are still debating the total. One source expected the final amount to land in the mid-to-late 70 trillion yen range, but said the security environment could demand more.

Japan’s proposed 70 trillion to 80 trillion yen defence programme would be about 1.8 times larger than the roughly 43 trillion yen allocated under its current five-year plan. The new programme would begin in April 2027, while the existing plan began in financial year 2023. This comparison shows how quickly Japan’s planned defence spending is expanding.

The current build-up programme was already a sharp increase from its initial allocation of 27.5 trillion yen. It focused on long-range missiles for counterstrike capabilities, plus ammunition and spare parts. The proposed plan would build on that earlier expansion rather than simply maintain existing spending.

The final figure could still change. One source said it might settle in the mid-to-late 70 trillion yen range. The government is still compiling the budget, revising three security-related documents and negotiating with coalition partners. A second source questioned whether even that amount would be enough for East Asia’s security environment.

The additional money could fund several capabilities, not one single weapons programme. A source said large numbers of drones were expected to be among the purchases. Japan is also developing domestically manufactured long-range missiles and prioritising artificial intelligence and space technologies. Together, these projects show a shift toward technology designed for modern, long-distance warfare.

Drones could help Japan respond to long-range attacks by supporting interception. The article links this approach to new fighting methods observed in conflicts in Ukraine and Iran. Long-range missiles would provide counterstrike capabilities, while AI and space technologies could support surveillance, decision-making and operations. The article does not specify the exact systems or spending shares.

The proposed spending range remains unsettled. Japan’s defence ministry has not commented on the new figure. Officials have said the country is exploring a defence structure centred on intercepting long-range attacks. Budget priorities will become clearer as the government revises its security documents and prepares the budget toward year-end.

The final defence spending figure depends on agreement within Japan’s government and ruling coalition. Two people familiar with the matter described the possible range, but both indicated that the number remains subject to change. Coalition partners are specifically involved in debating whether the proposed total is appropriate for the security environment.

The government must also compile the budget toward the end of the year and revise three security-related documents. Those steps will help shape the programme beginning in April 2027. The defence ministry is a central policy institution, but it said it had no comment at this point on the reported spending plan.

The negotiations could produce a figure below, within or near the proposed range. One source expected a result in the mid-to-late 70 trillion yen range. Another questioned whether that would be enough. The article does not identify the coalition partners or describe a formal approval timetable beyond the budget process and document revisions.

A weaker yen can make foreign-made defence equipment more expensive for Japan. If a supplier charges in another currency, such as dollars, Japan must exchange more yen to pay the same foreign-currency price. The equipment itself may not have become more costly in the supplier’s currency, but its yen cost rises.

For example, if a defence system costs a fixed dollar amount, a weaker yen increases the number of yen needed for the purchase. The same effect can apply to imported parts, maintenance and other procurement expenses. This mechanism can reduce how much equipment a fixed yen budget can buy.

The article directly links the weaker yen to higher defence equipment procurement costs. It does not identify particular foreign-made systems or give an exchange-rate example. This pressure could make the proposed 70 trillion to 80 trillion yen programme less powerful in practical purchasing terms, even before the government decides the final figure.

Japan has increased its focus on long-range missiles, drones and interception because officials see a changing security environment in East Asia. The country is exploring how to structure its defence around intercepting long-range attacks. This reflects concern that threats may arrive from far away and require faster, more capable responses.

The current build-up programme already prioritises long-range missiles intended for counterstrike capabilities, along with ammunition and spare parts. Japan is also considering large numbers of drones. Officials told Reuters that new methods of fighting seen in conflicts in Ukraine and Iran were influencing this approach. The article connects these lessons to Japan’s wider focus on AI and space technologies.

Japan is developing long-range missiles domestically and revising its security-related documents. The next five-year plan could provide 70 trillion to 80 trillion yen for these priorities. The final amount remains under debate. One source questioned whether even a mid-to-late 70 trillion-yen figure would match the region’s security demands.

A counterstrike capability generally means the ability to respond to an attack by striking the attacker’s relevant military assets, such as launch systems or bases. It differs from interception, which focuses on stopping or destroying an incoming missile or other weapon before it reaches its target. This distinction is based on established defence terminology; the article does not define the term itself.

Japan’s current build-up programme focuses on long-range missiles intended for counterstrike capabilities. Separately, officials said Japan is exploring a defence structure centred on intercepting long-range attacks, including through drones. In simple terms, interception tries to block the attack, while counterstrike seeks to respond against the source or supporting military capability.

The article does not describe Japan’s specific operational rules or targets. It does show that both capabilities are part of the wider planning debate. Japan is also prioritising ammunition, spare parts, AI and space technologies as it adapts to new forms of warfare and the East Asian security environment.