¥70 Trillion or More: Japan Weighs Nearly Doubling Its Five-Year Defence Budget

Japan spent most of the post-war era treating defence as something to be kept small, predictable and politically quiet. The figures now being discussed in Tokyo suggest that era is firmly over. According to people familiar with the talks, the government and the ruling coalition are weighing a five-year defence buildup worth between ¥70 trillion and ¥80 trillion, roughly $457 billion to $508 billion, for the period starting in April 2027.

That would be about 1.8 times the roughly ¥43 trillion set aside under the current programme, which began in fiscal 2023. Nothing has been finalised. The defence ministry has declined to comment, and the number could still move as the budget is compiled towards the end of the year. But even as a range under discussion, it tells us a great deal about how Prime Minister Sanae Takaichi sees Japan’s position in the region.

A plan that keeps getting bigger

The current programme is itself a sign of how quickly the ground has shifted. When it was drawn up at the end of 2022, planners lifted the envelope sharply from an initial allocation of ¥27.5 trillion. Much of that money was directed at long-range missiles meant to give Japan a counterstrike capability, together with something far less glamorous but just as important: ammunition and spare parts, the stocks that decide whether expensive equipment can actually be used for long.

The next plan would build on that base rather than replace it. In other words, Japan is not simply topping up a budget. It is moving from a first leap in spending to a second one, only a few years later.

Drones and a weaker yen

Two details reported from the discussions are worth highlighting. The first is what the money would buy. One source said the new spending is expected to fund large numbers of drones. That reflects a lesson militaries around the world have drawn from recent conflicts: cheap, numerous unmanned systems can change the battlefield as much as a handful of expensive platforms, and they need to be bought in volume.

The second detail is less about strategy and more about arithmetic. A weaker yen has pushed up the cost of buying defence equipment. Much of Japan’s high-end hardware, and many of the components inside domestically built systems, are priced in dollars. When the yen loses value, the same aircraft, missile or sensor simply costs more in yen. Part of any headline increase is therefore not new capability at all, but the price of standing still in purchasing-power terms.

This is an important point for anyone reading the figure as a pure signal of ambition. A larger yen budget does not translate one-to-one into a larger military. Some of it will be absorbed by exchange rates and by the general rise in the cost of complex systems.

How much is enough?

Even inside the discussions, the size of the plan is contested. One of the people familiar with the matter suggested the final figure could land somewhere in the mid-to-late ¥70 trillion range, while also questioning whether that would be sufficient given the security environment in East Asia. The final number, the same source said, is still a subject of debate between the government and its coalition partners.

That debate captures the dilemma facing Tokyo. On one side are the pressures that have driven the buildup so far: tension around Taiwan, China’s expanding military presence, North Korea’s missile programme and a growing expectation from Washington that allies carry more of the load. On the other side are the realities of Japan’s public finances, which already carry one of the heaviest debt burdens in the developed world, and a domestic agenda that includes relief for households struggling with the cost of living.

Where the money comes from

The question of funding is likely to become the political centre of this story. A plan of this scale cannot be financed by trimming a few line items. It raises uncomfortable choices: higher taxes, more borrowing, cuts elsewhere, or some combination of all three. Each option carries a cost. Tax rises are rarely popular, borrowing adds to an already large debt pile, and spending cuts in areas such as social security collide with the needs of an ageing population.

At the same time, the government is pushing measures that point in the opposite direction on revenue, such as efforts to ease the tax burden on food. Squaring a far larger defence plan with relief for consumers will test the coalition’s ability to explain its priorities clearly.

Three documents and a deadline

The spending decision is tied to a broader rewrite. The government is revising its three core security documents, the texts that define Japan’s strategy, its defence posture and the capabilities it intends to build. The budget and the strategy will be shaped together, which means the year-end process will be about more than money. It will also be about what kind of military role Japan is willing to accept for itself in the coming decade.

What to watch

Over the coming weeks, three things will matter most. The first is the final figure and whether it settles at the lower or upper end of the range. The second is how the government proposes to pay for it, and whether that sparks resistance inside the coalition or among voters. The third is the content of the revised security documents, which will show whether the money is meant mainly for deterrence through long-range strike, for resilience through stockpiles and drones, or for a broader transformation of the Self-Defense Forces.

Whatever the outcome, the direction is already clear. Japan is no longer debating whether to spend more on defence. It is debating how much more, how fast, and who pays.