For over six decades, the United States has been Japan’s primary foreign source of major defense systems through direct purchase and coproduction programs. Since the 1990s, this one-way transfer of defense equipment and technologies has expanded to include various cooperative research projects, licensed production of certain U.S. systems, and joint development of ballistic missile defense components. Japan revised its long-standing ban on arms exports in 2014, opening the way to broader defense industrial collaboration with the United States. But many challenges to bilateral collaboration continue to threaten the effective development of Japan’s newest and most ambitious defense program.

Though a critical enabler of alliance cooperation and highly beneficial to stakeholders in both countries, armaments cooperation programs have often proven controversial. By definition, defense acquisition programs blur the distinction between economic and defense matters, which conventional wisdom says should be kept separate in U.S.-Japan relations. U.S. efforts to promote its defense equipment and Japan’s focus on its defense industrial base sometimes go hand-in-hand, as in coproduction of the F-15 fighter. But “buy America” versus “develop in Japan” postures, aggravated by broader trade tensions, can also generate explosive controversy. During Japan’s FSX fighter program of the 1980s, concerns about economic competition and technology security frustrated positive engagement on what became Japan’s F-2 fighter aircraft.

All of these elements are visible in the emergence of Japan’s next fighter aircraft program—the F-3, successor to the current F-2. Over the next decade, the F-3 will become a critical matter—not only for the Japan Air Self-Defense Force’s capability, but also for the future of Japan’s defense and aerospace industries. Successfully defining a path to U.S.-Japanese collaboration on this program could make the F-3 an alliance-building centerpiece of cooperative defense acquisition. Failure to do so could trigger another FSX-like controversy and undermine prospects for future collaboration in defense capabilities development.


Since 2010, the Japanese Ministry of Defense (MoD) and industry engineers have been working on designs for an advanced fighter. Computer models depict a large, twin-engine multirole aircraft with fifth-generation technologies (notably stealth and fusion of sensor data), a concept very different from the smaller F-2 (which was derived from the U.S. F-16). The MoD embodied these goals in an Advanced Technology Demonstrator project unveiled in 2014. Stemming from this, U.S. and Japanese defense officials opened dialogue on the pursuit of common interests in fighter aircraft technologies.

The MoD’s references to plans for F-3 acquisition have varied over time, but information from government and industry sources indicate four options leading to introduction by 2035:

  • indigenous development of a new aircraft;
  • development of a new aircraft with foreign participation;
  • co-development (leading to joint procurement) with a foreign partner; or
  • procurement based on a derivate of an existing aircraft.

Japanese defense officials seem to recognize that complete indigenous development is unfeasible due to technological and financial constraints. Joint development with the United States is also impractical, given differing performance requirements and deployment timelines. This leaves two viable options: pursuing a new aircraft with some degree of international support, or working on a derivative of an existing aircraft. From 2016, the MoD’s Acquisition, Technology, and Logistics Agency (ATLA) issued a series of Requests for Information to potential foreign industry participants. Questions focused on both the products of three major aerospace contractors—Lockheed Martin’s F-35, Boeing’s F-15, and BAE Systems’ Typhoon—and their willingness to support a Japan-led fighter program.

U.S.-Japan Engagement

Differing approaches were evident from the beginning of U.S.-Japan talks on future fighter R&D cooperation. U.S. defense officials welcomed joint technology research but emphasized operational concepts and capability requirements as the basis for collaboration in fighter acquisition. Japanese counterparts, almost entirely drawn from ATLA R&D and procurement officials, continued to focus on technology development and industrial base interests.

This disconnect in priorities poses a critical challenge to productive engagement on the F-3 program. Dialogue focused only on industrial/technology base concerns cannot answer a critical question at the Pentagon: why should the United States support the development of a fifth-generation Japanese fighter? To justify the release of advanced U.S. technology, the U.S. Department of Defense requires an explanation for how contributing advanced technologies to Japan’s F-3 aircraft will strengthen alliance capabilities.

Shadows From the Past

Any discussion of F-3 development eventually circles back to Japan’s controversial FSX fighter program in the 1980s. Washington’s demand that Japan buy American versus Tokyo’s insistence on indigenous aircraft development was fueled by trade tensions at the time, unbalanced by any requirements-based evaluation of how the new fighter could serve alliance interests. The eventual solution—procurement of an F-16–derived F-2 fighter—was officially called co-development, though neither side really thought of it that way. The United States saw F-2 development as another exercise in security assistance for support of an F-16 variant in which it had no procurement interest. To Japan, the F-2 was an indigenous program based on an aircraft design imposed by pressure from Washington. Bitter memories in Japan of this program continue to cast a shadow on all discussions of U.S.-Japan cooperative defense activity.

After the FSX experience, the next U.S.-Japan bilateral engagement on combat aircraft was the 2007–2009 Airpower Assessment Study, a Capability Assessment Group (CAG) project borne of the security dialogue that flourished under former U.S. president George W. Bush and former Japanese prime minister Junichiro Koizumi. Despite positive interactions between direct participants, their talks never bridged differing objectives. U.S. officials stressed operational requirements for future air defense contingencies, while Japanese officials sought justification for the release of the United States’ newest crown jewel, the F-22 fighter. As Washington showed no signs of relaxing its F-22 export ban and attention shifted to the new F-35 fighter program, the airpower assessment dialogue (and the entire CAG initiative) disappeared; few on either side even recall the effort.

Recent Developments

Initially, ATLA planned to define its path to F-3 acquisition in Japan’s 2019 five-year procurement plan, the Mid-Term Defense Program. Although it had become evident by the summer of 2018 that the MoD was not prepared to make a firm decision on the F-3’s future, defense officials spoke of narrowing choices for pursuit in the next round of planning. At the same time, reports reached Washington that Japan was increasingly interested in collaborating with the United Kingdom on future fighter work. This introduced the F-3 to policy and political discussions in Washington and turned what had been an obscure matter into an alliance issue.

As U.S. officials emphasized the need for U.S.-Japan collaboration, talks between Tokyo and Washington became entangled by U.S. industry-supported lobbying for an F-3 solution based on a hybrid design of F-22 and F-35 fighter aircraft. Predictably, such activity triggered widespread speculation in Japan that if the F-3 were linked to U.S. President Donald Trump’s desire to increase defense sales and reduce the bilateral trade deficit, it could generate another FSX-like controversy. While Japan’s new Mid-Term Defense Program did commit Tokyo to substantially increase its purchase of America’s F-35—along with other expensive U.S. systems—the path forward for the F-3 remains unclear.

The UK Factor

Over the past several years, the UK and Japan have steadily expanded cooperation in defense planning, exercises, R&D projects, and industrial partnerships. The UK Tempest fighter concept, unveiled last summer, parallels the proposed F-3—a heavy, twin-engine, multirole aircraft with a long range, a high payload, stealth capabilities, and a similar timeframe for introduction (around 2035). Sources in both countries describe talks on fighter aircraft as open-minded and flexible, while emphasizing that discussion remains exploratory on specific areas for collaboration.

The UK and Japan clearly have converging interests in future fighter development. Post-Brexit Britain needs to look beyond EU partners for collaborators, while some Japanese officials see working with the UK as a way to avoid excessive U.S. restrictions on technology release and thus ensure real gains for Japan’s industrial base.

Reactions in Washington to UK-Japan discussions on future fighter interests have ranged from dismissive denial to real concern that Japan could turn its back on collaboration with the United States. By viewing U.S.-Japan and UK-Japan collaboration as an either-or choice, U.S. officials may be misguided. Both UK and Japanese stakeholders seem to recognize the need for U.S. support—and possible participation—in cooperation related to the F-3. The extent to which such engagement is possible will depend on progress in U.S.-Japan dialogue and their willingness to extend discussions to include the UK.


During recent discussions on F-3 development, Japanese MoD sources have emphasized their intent to:

  • keep all options open for development in the next Mid-Term Defense Program;
  • continue work on operational concepts for Japan’s fighter force;
  • ensure that the F-3 is a Japan-led project; and
  • resist pressure to force a particular solution on F-3 acquisition.

Industry sources report the MoD is interested in determining a path for F-3 acquisition within the next year or two, with a formal program launching soon after. Meeting such an ambitious timeline would depend on the MoD completing its evaluations of industry proposals, as well as determining terms for collaboration with the United States and/or other international partners—all of which requires an extraordinary degree of focus in staffing and negotiation both between governments as well as internally, among various interests on each side.

Private comments from U.S. officials indicate that there is little to show for efforts to develop more substantive dialogue on operational requirements. They believe that ATLA-led industrial/technology base interests continue to take the lead in their discussions with Japanese counterparts. Given a lack of substantive information from Japanese sources, there is still little understanding in Washington of what Japan’s F-3 fighter is intended to be, or why the United States should support its development. Such views only encourage holding a hard line on technology release and the permitted scope of U.S. industry support for F-3 development.

Meanwhile, sources in Tokyo describe a Japanese government position on F-3 acquisition that is, if anything, more explicit about the need for not only Japan-led development but also access to systems technologies needed to enable complete in-country maintenance and repair. From that perspective, a U.S. approach that offers access to systems hardware without underlying software, or know-how support in design and systems integration, is likely to be seen as another F-2, in fact if not name.

Japan and the United States have been here before. While U.S.-Japan relations now differ significantly from those that drove the FSX controversy thirty years ago, there is a disturbing similarity to that period. Talking past each other through miscommunication and the ease with which such a disconnect encourages hardline positions can morph into friction if not confrontation. As in the 1980s, each side has done little to belie suspicion and defensiveness from the other.

Beyond operational and technology security concerns, the prospect of political intervention looms large—pressure to follow a U.S. lead versus insistence on protecting an indigenous Japanese program. So far, dialogue on F-3 development has taken place largely among mid-level officials, with little executive engagement. Given evident intent in Japan to determine a path to F-3 acquisition in the near future, this issue must receive serious attention from policy-level officials before the ministerial-level meetings scheduled later this year. Positive engagement on the F-3 could still offer some basis for collaboration, which could defuse political tensions before they erupt. Continued disconnect will invite controversy, which responsible parties on both sides should seek to avoid.

Gregg Rubinstein is director of GAR Associates and served previously in the U.S. Departments of State and Defense, where he worked on U.S.-Japan defense and trade issues. He also worked in the private sector involving the United States and Japan, and he continues to consult for both government and private clients.