In mid-April 2026, Taiwanese media reported that the Republic of China Navy (ROC) is currently evaluating Japan’s upgraded Mogami-class frigate, known in the Japan Maritime Self-Defense Force as New FFM, is a candidate for its 6,000-ton next-generation surface combatant project. The report cited unnamed sources and suggested that Tokyo had quietly eased restrictions on the transfer of warship plans to Taipei.
Japanese authorities have not confirmed any of this. The report nonetheless remains significant. Five years ago, the political possibility he describes did not exist.
Taiwan’s interest in design is easy to understand. Of the Taiwan Navy’s approximately 25 main surface combatant ships, 15 have served more than 25 years; the Chi Yang class frigates are now more than 50 years old. Taipei is invest in indigenous people corvettes, a modernized Kang Ding fleet and a national submarine program (the lead boat, Hai Kun, carried out sea trials in 2025), but a single supplier base, even supplemented by the United States, will not close all the gaps. The more difficult question is whether Japan can become a second major democratic partner without breaking its own legal and political architecture in the process.
This architecture has evolved more in the last three years than in the previous three decades. In December 2023, the Kishida cabinet revised Japan 2014 Three Principles on the Transfer of Defense Equipment and Technology, authorizing limited exports of lethal equipment in five operational categories (rescue, transport, warning, surveillance and mine clearance) and allowing the re-export of licensed defense products to their country of origin. In March 2024, a second Cabinet decision authorized the export of the Global Combat Air Program fighter, co-developed with Britain and Italy, to countries with defense equipment transfer agreements with Japan. In February 2026, the Liberal Democratic Party (LDP) moved to abolish the five categories framework and replace it with a simpler classification of weapons and non-weapons. The Takaichi cabinet formally approved broader liberalization in April.
The political environment around these reforms also seems different. Komeito, long-time junior partner of the PLD and the most powerful internal brake on defense liberalization, finished his 26-year coalition with the LDP in October 2025. Prime Minister Takaichi Sanae, who won the general election in February with the support of Nippon Ishin no Kai, is more openly hawkish toward Taiwan than his predecessors.
After her parliamentary remarks in November 2025 on a possible eventuality in Taiwan, China imposed a series economic measures against Japan. On January 6, Beijing tightened controls on exports of dual-use products to Japanese military end-users, followed on February 24 by the addition of 20 Japanese defense companies, including Mitsubishi Heavy Industries, Kawasaki and IHI, to Beijing. List of controlled exports. By any reasonable measure, China is already retaliating against Japan as if Tokyo were directly arming Taipei.
In August 2025, Canberra selected upgrade Mogami as the preferred platform for the Royal Australian Navy’s multi-role frigate program. In April 2026, Australia signed the formal contract with Mitsubishi Heavy Industries for the first three vessels, with the remaining eight to be built in Western Australia under technology transfer agreements. The first three frigates are valued at around A$10 billion, with the wider program expected to reach around A$20 billion over the decade. The ships displace approximately 3,900 tons, operate with a crew of approximately 90, and combine anti-submarine, anti-surface and air defense capabilities, making the Mogami class a multi-role design intended for sustained operations in the Indo-Pacific.
What makes the deal substantial is the architecture around the platform. Tokyo established a dedicated joint committee to coordinate the application, agreed to a substantial transfer of intellectual property, and integrated the program into a broader security relationship between Australia and Japan anchored by the Reciprocal Access Agreement. The result, rather than a one-off sale, is a decades-long industry partnership. The importance of these arrangements extends beyond shipbuilding itself; Japan’s industrial capacity is a critical supplement the sustainment of the United States in times of war and the production of munitions in a Taiwanese scenario.
Any comparison between Japan’s defense diplomacy with Australia and with Taiwan has obvious limitations. Between Japan and Taiwan, there is no diplomatic recognition, no defense equipment transfer agreement, no reciprocal access agreement, and no obvious legal pathway under current rules for the direct sale of a completed Japanese warship. Even if the April 2026 reports prove accurate, sharing plans is not the same as buying a frigate.
It is therefore appropriate to be specific about what the Mogami Agreement could and could not model for Taipei. It cannot model an immediate sale on the platform. It can model the policy scaffolding, step-by-step industrial logic, and long-term partnership that Japan and Taiwan would need to build together over time.
Any serious cooperation framework will probably have to develop gradually. The first step is cooperation between the coast guard and dual uses: maritime surveillance sensors, oceanographic systems, communications networks and patrol boats. Japan’s Official Security Assistance program already supports the Philippines, Indonesia, and Bangladesh in similar ways, and Taiwan’s coast guard already conducts operational-level exchanges with its Japanese counterpart. A discreet expansion of this cooperation would not require a revision of the export framework.
The second step is cooperation at the component level. Sonar arrays, radar modules, electronic warfare elements, and unmanned vehicle subsystems can in many cases be transferred under current rules, especially when integrated into Taiwan’s national shipbuilding programs. Japan’s co-production of UNICORN stealth antennas with India provides a precedent for component transfer that does not require the export of a complete weapons system.
The third stage is sustainment, training and personnel exchange. The Australian Mogami Agreement is most directly relevant here. The contract with Mitsubishi Heavy Industries is contingent on knowledge transfer, workforce development and long-term fleet support. Similar logic, applied to Taiwan’s existing programs and systems that the two navies could share or compatibly operate, would increase operational readiness yields over time, without requiring the export of new platforms.
A fourth step, conditional on political conditions in Tokyo, could one day extend to platform-level cooperation or joint development of next-generation systems. This step is not available today. This would likely require a defense equipment transfer agreement that Taiwan does not have, and a Japanese domestic consensus that is not yet visible.
There are obvious obstacles to this approach, but each is surmountable. Beijing will retaliate against Japan regardless of what Tokyo does for Taipei; the only question is whether Japan will receive a strategic return for the costs it is already paying. Taiwan prefers American systems, but its local platforms already integrate components from several democratic suppliers, and Japanese sensors and sustainment would complement rather than replace American capabilities. Japanese companies remain cautious about a politically sensitive market, but Mitsubishi, Kawasaki and IHI already have complex export relationships in the region. Japanese public opinion is divided over arms exports, calling for a gradual approach rather than paralysis.
Japan’s National Security Strategy for 2022 already cites the Taiwan Strait as a direct concern. The scope of Tokyo’s defense industry has grown faster than the political vocabulary used to discuss it. A measured, phased Japan-Taiwan framework, anchored in Coast Guard support, components, and sustainment, with platform-level cooperation deferred but not ruled out, would help close some of this gap. Tokyo has shown that it is capable of building lasting partnerships between the defense industry and the defense industry when it wants to. The remaining question is whether this capability will be directed toward the partner whose security needs are most pressing and toward whom restraint will not be rewarded.