Japan’s new National Defense Program Guidelines (NDPG) calls for more attention to areas such as space, cyber, and the electromagnetic spectrum. Critical reaction to the NDPG in Japan, however, has centered around the decision to convert two Izumo-class helicopter “destroyers” into multirole aircraft carriers from which short takeoff and vertical landing (STOVL) aircraft can be operated. To that end, the NDPG also lays out a plan to purchase 42 Lockheed Martin F-35B STOVL aircraft over the next decade. Critics argue that these ships, equipped with F-35Bs, must now be considered “attack aircraft carriers” and constitute a departure from Japan’s defense-oriented security policy.
Serving as the link between the “ends” outlined in Japan’s National Security Strategy, and the “means” listed in the Mid-Term Defense Plan, the NDPG describes the “ways” Japan will achieve its security objectives. Intended to last ten years, the 2013 NDPG was revised ahead of schedule, reflecting the government’s concern over the increasingly difficult security environment.
At Defense Minister Takeshi Iwaya’s 18 December press conference, nearly half of the 25 questions asked concerned the Izumo or, more generally, the definition of an “attack aircraft carrier.” Similarly, commentary and editorials in Japanese media following the announcement included strong condemnations of this perceived step toward militarism.
However, the characterization of an F-35B-equipped Izumo-class ship as an offensive-oriented weapon system and a radical departure from Japan’s defensive-oriented security policy is mistaken. Modifying the Izumo-class ships to operate STOVL aircraft is a valid means-to-the-ends as described in Japan’s National Security Strategy, does not make them offensive weapons platforms, and does not constitute a threat to other countries’ territory or sovereignty.
Defending Japan Means Sea Control
As an island nation with limited natural resources, Japan depends on access to the sea. Japan, supported by the United States, must be able to deter and prevent potential enemies from denying it the use of its waters, both for seaborne commerce and to protect its offshore islands. Japan’s interpretation of its postwar constitution always has included the right of self-defense to ensure national survival.
Critics who charge that the Izumo upgrade violates the constitutional ban against offensive weapons confuse tactics with strategy. Judgments of offensive and defensive capability must be made at the strategic level by elected political leaders. Offensive tactics are essential within a successful defensive strategy. In his classic book on naval warfare, Fleet Tactics, retired Navy Captain Wayne Hughes argues that “all fleet operations based on defensive tactics (but not defensive forces) are conceptually deficient. A successful defensive naval strategy entails a concentration of force and a successful tactical attack” (emphasis added).
A defensive military operation to defend Japan’s use of the sea is complex, with many components. As the “Guidelines for Japan-U.S. Defense Cooperation” state, “The Self-Defense Forces will have primary responsibility for the protection of major ports and straits in Japan and of ships and vessels in waters surrounding Japan and for other associated operations. For this purpose, the Self-Defense Forces will take necessary actions, including, but not limited to, coastal defense, antisurface warfare, antisubmarine warfare, mine warfare, antiair warfare, and air interdiction.” An operation to take back the Senkaku Islands from Chinese special operations forces would require similar operations and capabilities.
The Tactics to Support a Defensive Sea-Control Strategy
An Izumo-class ship operating 10–20 STOVL aircraft would substantially increase the capabilities of the Japan Maritime Self-Defense Force (JMSDF) in three areas covered in the Defense Cooperation Guidelines: Antisurface warfare, antiair warfare, and air interdiction. Izumo-class ships operating with JMSDF submarines and surface combatants, Japan Air Self-Defense Force (JASDF) land-based fighters, and Japan Ground Self-Defense Force (JGSDF) coastal-defense missiles would be able to control Japan’s vital sea areas against Chinese naval task forces with advanced surface ships, as well as land- and sea-based missiles and aircraft. By operating F-35B aircraft from Izumo-class ships, the JMSDF will be able to extend its surveillance and reconnaissance and defensive weapons range by hundreds of miles.
The challenges to defending the Self-Defense fleet against aircraft armed with cruise missiles (or hypersonic glide weapons) underscore the need to upgrade the Izumo class to operate the F-35B STOVL aircraft, as the average range of ship-killing missiles is in the hundreds of miles while the average range of defensive ship-launched antiaircraft and antimissile missiles is only about 100 miles. Similarly, cruise-missile-armed ships and patrol boats pose a dangerous threat to the Self-Defense fleet. Detecting and destroying attacking ships and aircraft before they can launch their weapons is the best means of defending the Self-Defense fleet. Izumo-class ships operating STOVL aircraft are part of that defense.
Izumo-class ships operating F-35B would be valuable in other sea-control roles as well. Armed with shortrange antiship missiles, the F-35B would be very effective against “swarm tactics” by patrol craft or maritime militia vessels. In an “island grab” scenario, the F-35B would be invaluable in establishing the local air control required for Japan’s new amphibious regiment to retake remote islands.
The Path to a More Effective Defensive Sea Control Strategy
The value of tactical aviation to the Self-Defense fleet extends beyond the short-term. Areas ripe for long-term improvement, such as doctrine, tactics, and experimentation, offer opportunities for improved cooperation with U.S. forces.
Doctrine. The Chief of Naval Operations explains the U.S. Navy’s plan for countering an advanced opponent in the recently released strategy document, “A Design for Maintaining Maritime Superiority, 2.0.” This design envisions a networked force of manned and unmanned systems operating in dispersed, independent, highly effective tactical units that coordinate and integrate their actions. While Japan’s strategy for sea control will be different, it will contain many of these same concepts driven by technological developments. An Izumo-class ship operating STOVL aircraft and antisubmarine helicopters will be a key part of Japan’s future maritime strategy.
Tactics. The F-35B is a capable platform. Payloads, however, are more important than platforms. In other words, what weapons and sensors the F-35B carries into battle are what really matter. Moreover, weapon systems technology is evolving rapidly with the incorporation of autonomy, hypersonic airframes, and advanced terminal maneuver, requiring continual and rapid reassessment of weapons and tactics to assure effectiveness. The U.S. Navy and the JMSDF share the challenge of deterring and defeating a potential adversary with a capable and growing arsenal of high-performance missiles. Japan’s purchase of the Joint Strike Missile, Joint Air-to-Surface Standoff Missile, and Long Range Anti-Ship Missile is a positive development and will require effective tactics for their employment in the maritime domain.
Experimentation. The integration of F-35B with Izumo-class ships will allow the JMSDF to gain valuable experience with sea-based tactical aviation. The JMSDF also should view this as an opportunity to work with U.S. forces to experiment with new doctrine, tactics, and platforms. Izumo-class ships would make an ideal platform for experimenting with unmanned air vehicles (UAVs) equipped with a variety of mission kits. Another candidate for shipboard experimentation is the V-22 Osprey, which Japan is acquiring and U.S. forces already are operating in Japan. Other manned platforms in development that show promise for maritime application include innovative entries in the U.S. Army’s Joint Multi-Role Technology Demonstrator program, such as the Bell V-280 Valor tiltrotor aircraft and the Sikorsky-Boeing SB-1 Defiant vertical-lift compound helicopter. Integrated with existing technology, such manned and unmanned air systems could perform airborne early warning, electronic attack, sea surveillance, antisubmarine warfare, or aerial refueling missions. Operating from Izumo-class and other air-capable JMSDF and U.S. Navy ships, these platforms could make any node in a distributed, networked maritime force more resilient and lethal.
China’s rapid buildup of advanced weapons and maritime and air forces, and its aggressive gray-zone actions and belligerent nationalist rhetoric have altered the security environment in Northeast Asia. Unless Japan accelerates its own military modernization and growth, it will not keep pace with the threat. China will press a military advantage sufficient to make bolder and more aggressive moves.
Japan’s interpretation of its constitution allows for defensive forces sufficient to ensure national survival. As a maritime nation, Japan’s survival and well-being are inextricably linked to the sea. China’s aggressive moves in the maritime domain threaten Japan’s well-being and the sovereignty of its offshore islands. Improving the means by which Japan’s Self-Defense Forces can deter and counter China with a defensive sea-control strategy is a reasonable and important step.
In the short-term, modifying Izumo-class ships to operate STOVL tactical aircraft will provide the Self-Defense fleet, in concert with JASDF, JGSDF, and U.S. forces, an effective means to conduct the offensive tactics required for a defensive sea-control strategy. In the long-term, this capability will provide avenues for further growth in tactics, doctrine, and experimentation. In this way, Japan will add credibility to its armed deterrent and—if deterrence fails—improve its capacity to protect its territorial seas, ensure access to the maritime commons, and repel an invasion of its more remote offshore islands.