Japan's Full-scale Launch of "Counterattack Capability": The Deployment of the Improved Type 12 Surface-to-Ship Guided Missile Indicates a Strategic Shift

In March 2026, a significant movement that marks a historic turning point in Japan's defense policy materialized. The Japan Ground Self-Defense Force completed the initial deployment of the improved Type 12 surface-to-ship guided missile at the Kengun Garrison in Kumamoto Prefecture, with expectations to reach Full Operational Capability (FOC) by the end of March. This deployment symbolizes a major shift from the "defense-only" principle that has defined Japan's post-war defense policy and could have a substantial impact on the security environment in East Asia.

The improved Type 12 surface-to-ship guided missile is a significantly enhanced version of the conventional Type 12 SSM (which began deployment in 2015), developed by Mitsubishi Heavy Industries. The most notable improvement is the dramatic extension of its range. While the conventional version had a range of about 200 kilometers, the improved version is said to reach over 900 to 1,000 kilometers. Although the Acquisition, Technology & Logistics Agency has not released official figures, this range would allow it to cover not only the entire Taiwan Strait but also parts of the Chinese coastline.

From a technical perspective, the improved Type 12 achieves multifaceted capability enhancements beyond mere range extension. The shape of the missile body has been redesigned to reduce radar cross-section (RCS), improving its stealth characteristics. It uses a booster at launch and employs a small turbo-fan engine during cruise flight, enabling long-distance travel. The navigation system integrates satellite positioning, inertial navigation, and terrain contour matching (TERCOM) capabilities, allowing for precise low-altitude flight. In the terminal guidance phase, a system combining radar and image guidance is employed, capable of addressing both stationary and moving targets. Furthermore, mid-course corrections via data link are possible, and maneuver options that reduce the effectiveness of defense systems are reportedly incorporated.

Innovations in operational aspects are also noteworthy. The improved Type 12 employs a mobile launch system mounted on an 8×8 tactical truck, allowing for deployment, launch, and rapid repositioning. This significantly enhances survivability against enemy counter-battery fire. Following its deployment to the 5th Surface-to-Ship Missile Regiment at Kengun Garrison, plans are in place for sequential deployments to the 8th Surface-to-Ship Missile Regiment in Oita Prefecture and the 7th Surface-to-Ship Missile Regiment in Okinawa over the next few years.

The strategic implications of this deployment are extremely significant. First, it clearly indicates a shift in Japan's defense posture from "homeland coastal defense" to "distant deterrence." Traditionally, Japan's surface-to-ship missiles were primarily aimed at dealing with vessels in its territorial waters and contiguous zones. However, the range of the improved Type 12 could reach vessels passing through the Taiwan Strait and naval bases along China's eastern coast. This effectively represents the acquisition of "counterattack capability," materializing the policy of "possessing counterattack capability" outlined in the national security strategy approved by the Cabinet in December 2022.

Second, this deployment reflects a change in Japan's role within the framework of the U.S.-Japan alliance. The long-standing Yoshida Doctrine relied on the U.S. military's security umbrella for Japan's defense, limiting the size and capabilities of the Self-Defense Forces. However, the military rise of China and advancements in North Korea's nuclear and missile development have significantly shaken this premise. Prime Minister Sanae Takaichi has shown a cautious stance toward U.S. President Trump's request for support in the Strait of Hormuz while actively lobbying for cooperation in the Golden Dome initiative and the stability of trade and defense. This can be seen as a new approach that transcends the dichotomy of the Yoshida Doctrine's "economic priority, defense restraint," seeking a balance between economic and security considerations.

Third, this deployment is also important in the context of Japan's participation in the QUAD (U.S.-Japan-Australia-India Strategic Dialogue). The QUAD was formed as a security framework against China's expanding influence, and by demonstrating a willingness to take on a more active military role, Japan could enhance the effectiveness of this framework. Particularly in scenarios involving a Taiwan contingency, Japan's ability to operate long-range surface-to-ship missiles from the southwestern islands toward the Taiwan Strait could have a significant impact on the operational plans of the People's Liberation Army Navy (PLAN).

However, this strategic shift comes with challenges. The greatest concern is the compatibility with Article 9 of the Japanese Constitution. Article 9 stipulates the "renunciation of war" and "non-maintenance of military forces," but since the establishment of the Self-Defense Forces in 1954, the government has maintained its constitutionality under the interpretation of "the minimum necessary force for self-defense." The constitutional debate over whether the possession of long-range strike weapons like the improved Type 12 falls within this "minimum necessary" framework is unavoidable. The government defines "counterattack capability" as "the minimum necessary self-defense measures to prevent armed attacks against our country in the opponent's territory," but it remains unclear how widely this interpretation will be accepted both domestically and internationally.

There is also a risk of accelerating regional arms races. China views Japan's deployment of the improved Type 12 as a "crossing of a strategic threshold," and it is highly likely that the Xi Jinping administration will take countermeasures. Specific actions could include strengthening military activities in the East China Sea and South China Sea, increasing the frequency of exercises around Taiwan, and deploying new weapons aimed at intimidating Japan. This could create a vicious cycle, further escalating regional tensions.

In terms of technological development, Japan is advancing the development of even more advanced strike systems beyond the improved Type 12. The hypersonic guided missile (HVGP) currently under development by the Acquisition, Technology & Logistics Agency involves a hypersonic glide body launched by a ballistic missile to reach targets at extremely high speeds. According to the International Institute for Strategic Studies (IISS), the initial model is said to have a range of about 500 kilometers. Additionally, the "new anti-ship guided missile" being developed through Kawasaki Heavy Industries is designed to have a longer range and enhanced maneuverability in the terminal phase, capable of penetrating defense systems. As these weapon systems are integrated with the expansion of reconnaissance satellite networks and the establishment of the Amphibious Rapid Deployment Brigade (Japan's version of the Marine Corps), Japan's defense posture is undergoing a significant qualitative transformation.

The deployment of the improved Type 12 signifies that Japan has acquired a full-fledged "distant strike capability" for the first time since the war. This is not merely an update of equipment but a transformation of Japan's defense philosophy itself. How to position "counterattack capability" within the framework of defense-only, how to redefine roles within the U.S.-Japan alliance, and how to maintain regional stability—answers to these questions will shape the future of security in East Asia.