Deployment of Japan's First Domestic Long-Range Missiles and a New Phase in the Japan-U.S. Alliance: Strategic Implications of Building Counterstrike Capability

The Japanese government officially announced on March 9, 2026, its plan to deploy the improved Type 12 surface-to-ship guided missile, developed by the Ground Self-Defense Force, to Kumamoto Prefecture by the end of the month. The operational deployment of this domestically produced long-range missile, which has a range of 1,000 kilometers, symbolizes a historic turning point in Japan's post-war defense policy and signifies the realization of the "counterstrike capability" decided by the Cabinet in December 2022. Defense Minister Minoru Kihara stated at a press conference that he would provide detailed explanations to local municipalities regarding the deployment in southwestern Kyushu, but there have been criticisms from local residents about the Ministry of Defense's lack of information.

The improved Type 12 missile significantly extends the range of the conventional Type 12 surface-to-ship guided missile (with a range of about 200 kilometers), allowing it to cover a wide area from the southwestern islands to the coastal areas of the Korean Peninsula and China. This deployment reflects Prime Minister Sanae Takaichi's recognition of "the most severe and complex security environment since the war," as stated during the graduation ceremony of the Defense Medical University on March 9. Prime Minister Takaichi also expressed her intention to revise the three security-related documents within this year to achieve strategic evolution.

The background to this long-range missile deployment is the ongoing diplomatic crisis between Japan and China that has persisted since the end of 2025. Since Prime Minister Takaichi mentioned the possibility of the Self-Defense Forces' intervention in the event of a crisis in the Taiwan Strait, diplomatic protests and public warnings have continued between the two countries. According to a government survey conducted in January 2026, 68% of Japanese citizens cited China's military technological advancements and activities in the South China Sea as their greatest security concern, surpassing the issue of North Korea's missiles. This trend in public opinion clearly indicates a change in threat perception within Japan's defense strategy.

Alongside the deployment of long-range missiles, the substantive deepening of the Japan-U.S. alliance is also accelerating. From February 23 to 27, 2026, a joint fleet synthetic training (FST-J 26-71) was conducted at the Yokosuka Naval Base and various command centers in the region. This exercise is part of the maritime segment of the Japan-U.S. integrated air and missile defense (defensive) exercises, aimed at providing computer-generated training to land command and naval vessels, refining ballistic missile defense coordination in complex operational environments.

The exercise included the USS Shoup (DDG-86), an Arleigh Burke-class guided missile destroyer from the U.S. Navy's 70th Task Force, as well as the JS Maya (DDG-179), a Maya-class guided missile destroyer, and the JS Kirishima (DDG-174), a Kongō-class guided missile destroyer from the Japan Maritime Self-Defense Force. Rear Admiral Eric Anduze, commander of the U.S. Navy's 70th Task Force, stated, "Through fleet synthetic training, both U.S. and Japanese teams can exercise under challenging scenarios and improve joint operations. This training enhances deterrence by ensuring a posture that defends both nations and maintains security across the Indo-Pacific region."

FST-J 71 is a regular readiness activity aimed at strengthening coordination among the U.S. Navy, Japan Maritime Self-Defense Force, Japan Air Self-Defense Force, and Japan Ground Self-Defense Force. Such exercises support forward-deployed operations and reaffirm the Japan-U.S. alliance as a cornerstone of regional security. Notably, it focuses on enhancing command and control, decision-making, and defensive responses while protecting sensitive capabilities. This indicates that interoperability between Japan and the U.S. is deepening from the tactical level to the strategic level.

Furthermore, Japan's defense technological innovation is steadily progressing. The Ministry of Defense conducted its first test of AI-equipped unmanned aerial vehicles (UAVs) capable of autonomous decision-making based on sensor data in November 2025, with plans for flight tests in combat and reconnaissance scenarios from 2026 to 2027. This move signifies Japan's entry into the trend of developing autonomous weapon systems promoted by advanced countries such as the United States and Israel.

In terms of defense budget, Japan plans to increase its defense spending from 5.4 trillion yen (approximately $40 billion) in 2022 to 8.9 trillion yen (approximately $66 billion) by 2027, a 65% increase, aiming to raise overall defense-related spending to 2% of GDP. The multi-year investment plan totaling about 43 trillion yen aims not only to develop counterstrike capabilities but also to enhance stand-off defense capabilities, integrated air and missile defense, cross-domain operational capabilities, and sustainability and resilience.

However, these enhancements in defense capabilities may impact the regional military balance. China has criticized Japan's deployment of long-range missiles as a "provocative act that heightens regional tensions," and North Korea has shown a similar reaction. Additionally, South Korea is also advancing its own defense capabilities, raising concerns about an arms race in East Asia.

On the other hand, Japan's possession of counterstrike capabilities is justified from a deterrence perspective. Maintaining the framework of exclusively defensive posture while possessing the ability to respond to military targets within the adversary's territory has a deterrent effect. Particularly in scenarios involving crises in the Taiwan Strait or around the southwestern islands, Japan's possession of a certain level of striking power complements the credibility of U.S. extended deterrence and strengthens the overall deterrence of the alliance.

The deployment of the improved Type 12 missile to Kumamoto Prefecture provides strategic depth for the defense of the southwestern islands. By using southern Kyushu as a launch base, it enhances mobility and survivability, especially as deployments to Okinawa and the Sakishima Islands face political and geographical constraints. In the future, if mobile launchers are deployed and dispersed, the ability to avoid neutralization by a first strike will also improve.

From the perspective of the Japan-U.S. alliance, the regularization of synthetic training like FST-J 71 is crucial. Alongside large-scale exercises that mobilize actual vessels, repeated integrated training in computer-generated environments will enable improved interoperability from peacetime and cost-effective readiness maintenance. Particularly in ballistic missile defense, the timeline from detection to tracking to interception is extremely short, making seamless information sharing and command and control coordination between Japan and the U.S. essential.

A future challenge is to strengthen dialogue with local residents. According to reports from the Mainichi Shimbun, protests arose from local residents during the movement of launch equipment on March 9, criticizing the Ministry of Defense for its lack of explanations. Sustainable defense capability development is difficult without the understanding and support of the public, and there is a need for transparent information provision and careful explanations.

Additionally, clarifying the operational rules for counterstrike capabilities and the political decision-making process is also important. Demonstrating to the public the criteria for decision-making that leads to actual use, including distinctions from preemptive attacks, legitimacy under international law, and consultation mechanisms with the United States, will enhance the credibility of the policy.

In conclusion, the deployment of the improved Type 12 missile and the deepening of Japan-U.S. integrated training represent an important step in the evolution of Japan's defense policy from "shield" to "shield and spear." In response to the most severe security environment since the war, characterized by China's military rise, North Korea's nuclear and missile threats, and tensions in the Taiwan Strait, Japan is advancing the construction of realistic deterrence capabilities. Whether this move contributes to regional stability or leads to an arms race depends on future diplomatic efforts, ensuring transparency, and close coordination with allies. For the Japan-U.S. alliance to continue playing its role as a public good in the region, efforts for dialogue and trust-building must continue alongside military capability enhancement.