From Partnership to Capability: The NATO–Japan Defense Industrial Cooperation
By Asako Takashima
Japan became NATO's most engaged Indo-Pacific partner after former Japanese Prime Minister Kishida warned in 2022 that “today's Ukraine may be tomorrow's Indo-Pacific.” The message, which came after Russia invaded Ukraine, suggests there’s a risk of similar territorial aggression in East Asia. Soon after, Japan became NATO’s most engaged Indo-Pacific partner. In 2022, at the group's summit in Madrid, it founded the Indo-Pacific Four (IP4)—an alliance of NATO partners from the region—together with South Korea, Australia, and New Zealand, and in 2025, it became the only IP4 country with an independent mission to NATO in Brussels.
Since Kishida stepped down in 2024, neither of his successors—Shigeru Ishiba nor current Prime Minister Sanae Takaichi—has matched his enthusiasm for this form of diplomacy. Yes, both have skipped the last two NATO summits, but political attendance is the wrong metric for assessing this relationship. Instead, defense-industrial cooperation should serve as the measure of progress.
In the time since Kishida’s 2022 warning, the structural logic for deeper North Atlantic–Indo-Pacific security cooperation has only strengthened: North Korean troops are now fighting in Ukraine, and the Russian defense industry is leaning on China more than ever. Russian allies are taking lessons from what is happening in Ukraine and however the war ends will play into whatever ensues next in East Asia. As a result, the core of Japan–NATO partnership is shifting from political engagement to defense-industrial cooperation, which is where progress should be measured.
Japan’s Defense Industrial Revival
This past April, Japan lifted its long-held five-category rule, which restricted arms exports. The rule limited the transfer of defense equipment to five categories: rescue, transport, surveillance, minesweeping, and mine clearance. Now, the country is positioning its defense industry to sell abroad.
The decision wasn’t a sudden one, but the culmination of many years of incremental loosening. Starting in 1976, Japan was under a blanket ban on exporting defense equipment. It lasted until the Three Principles on Transfer of Defense Equipment and Technology in 2014, which specified three cases when Japan could export arms. A December 2023 revision allowed equipment produced in Japan under foreign license to be exported back to the licensing country. Next, a March 2024 exception opened exports of the Global Combat Air Programme (GCAP)—a trilateral next-generation fighter aircraft program with Japan, the United Kingdom, and Italy—to third countries. This most recent revision from April has further lowered regulatory barriers by replacing the five non-combat categories with a simpler distinction between weapon and non-weapon. This has expanded the opportunities for Japan’s defense industry to integrate into NATO defense supply chains.
Currently, the flagship of Japan–NATO defense industrial cooperation is the GCAP. While a promising achievement, though, GCAP should not serve as a template for a NATO–Japan partnership. Europe's own experience with the Future Combat Air System (FCAS)—a program that collapsed in June 2026 after years of industrial infighting over workshare and intellectual property rights—shows that major joint-development projects are rare, expensive, and politically contentious. Any future Japan–NATO joint development projects that prove successful should therefore be viewed as the exception rather than benchmarks for progress.
Measures of Success
With Japan–NATO cooperation now increasingly related to developments in the defense-industrial field, progress should be measured by three benchmarks: procurement, standardization, and people.
Procurement is a legitimate form of cooperation, and it is already making an impact. Japan has ordered additional Joint Strike Missiles from Norway's Kongsberg defense and aerospace company. This is notable because Japan’s liberalized export rules point toward reciprocal sales into the NATO market. Also, Japan has already delivered Patriot Advanced Capability-3 missiles to the United States. To avoid the risk of this becoming a sales competition rather than defense industrial cooperation, policymakers on both sides should recognize procurement as a valid measurement of cooperation. They should streamline procurement processes and track the processes alongside joint development as an indicator of a strengthened relationship between the countries in question.
The second benchmark is standardization. Without common specifications, calibers, and interfaces for missiles, ammunition, and the platforms that carry them, reciprocal purchases act as one-off transactions rather than an interoperable supply chain. NATO's experience in harmonizing standards among its own members is a template that Japan and NATO could adapt. A standing forum on shared specifications and subsystems—where agreeing on common technical standards before individual procurement decisions lock in incompatible designs—would be a useful next step for interoperability.
The third benchmark is people. NATO's Science and Technology Organization—a defense network of researchers and engineers with more than 6,000 people to date—is open to Japan as a partner nation and is exactly where new “demand” gets discovered before anyone thinks to ask for it. The obstacle is mundane: NATO’s Brussels headquarters is far from Tokyo, and the companies and universities that employ Japanese researchers have little incentive to fund repeated long-haul trips for open-ended collaboration. A modest, jointly funded travel and exchange program, piloted with a few dozen fellowships and judged on the partnerships it produces, would cost little relative to any single procurement contract. The potential impact of such a program, though, could be enormous for seeding the next generation of defense projects.
None of these benchmarks require new agreements. Rather, they simply demand an investment in the unglamorous parts of the relationship. Driving progress in these areas is how NATO and Japan can further solidify their cooperation.