Making Japan’s Rapid Deployment Forces Better

The mission of the Japan Ground Self-Defense Force (JGSDF) is to deter and respond to aggression against Japan. The nation comprises a 3,000-kilometer-long (1,800-mile) chain of islands—many quite remote—oriented along a line that runs northeast to southwest. The JGSDF has been undergoing a dramatic restructuring to strengthen its remote-island defense capabilities: establishing new units, improving capabilities for deploying brigade- and regiment-sized units to remote locations, and upgrading the capabilities of the Amphibious Rapid Deployment Brigade (ARDB).

In the early stages of any conflict, it would take a great deal of time to deploy many of the JGSDF’s conventional units to remote regions, in particular the southwest islands that extend from Okinawa to the Sakishima island group. At the farthest end is Yonaguni, which lies a mere 70 miles from Taiwan. Therefore, the JGSDF needs to enhance its rapid-deployment forces, making them more capable of moving out within a few hours to halt an invasion until larger ground force units can reach the fight. However, the JGSDF’s current readiness structure and training system for rapid-deployment forces make it difficult to operate effectively and improve its capabilities.¹

To develop credible, flexible rapid-deployment forces—a true Rapid Deployment Force (RDF)—the JGSDF should improve its readiness system and update its training requirements.

Train and Equip Like You Fight

Many countries maintain forces specially trained to quickly deploy combat power in emergencies through airborne and amphibious operations. Examples include U.S. Marine expeditionary units (MEUs; two MEUs are generally on standby at sea); the Immediate Response Force drawn from U.S. Army airborne units and elements of the U.S. Air Force; and the airborne-capable multinational NATO Response Force.²

At present, the JGSDF’s most rapidly deployable elements are the 1st Airborne Brigade (three battalions) and the ARDB (three regiments), but open-source documents do not specify their deployment capabilities. In peacetime, most ground units are under the control of regional operational commands. But the ARDB and 1st Airborne Brigade are always under the direct control of the Ground Component Command, which would take command of some or all JGSDF ground forces in the event of a contingency.³ Since the ARDB depends on its Assault Amphibious Vehicle 7s (AAV-7s) and focuses primarily on the mission of recapturing remote islands, the 1st Airborne Brigade is generally considered the most suitable JGSDF unit for rapid deployment at present.

The readiness system is inadequate in terms of logistics and equipment, making immediate and flexible deployment difficult. Neither the ARDB nor the 1st Airborne Brigade has sufficient organic air or sea transport to deploy to the southwest islands on its own in an emergency.

The Japan Air Self-Defense Force (JASDF) currently possesses 30-some transport aircraft, including 16 Kawasaki C-2s (capable of carrying about 100 passengers) and 13 C-130Hs. The Japan Maritime Self-Defense Force (JMSDF) has three Ōsumi-class tank landing ships (LSTs). However, considering maintenance and other factors, not all ships and aircraft would always be available.⁴ These numbers are insufficient to meet the intensive transportation demands of airborne and amphibious contingency operations, especially the possible invasion of Japan’s most remote islands that is anticipated as part of any conflict over a neighboring country.

The Japan Self-Defense Force (JSDF) must maintain a logistics support system that takes into account both rapid deployment to the southwest islands region and Japanese noncombatant evacuation operations (NEOs), but the current posture will be insufficient for transportation requirements.⁵ Of note, more than 10,000 Japanese nationals are located in Taiwan.

In addition, current rapid-deployment forces do not possess the right equipment in the right places to deploy in a contingency. In contrast, III MEF’s organic matériel is prepared for ready deployment and contains the items the Marines will need to get into the fight quickly. Even in the highly intelligence-enabled world of modern warfare, enemy attacks may begin with surprise incursions—such as Russia’s invasion of Ukraine or Hamas’s surprise attacks in October 2023—and require a rapid response from a 24-hour alert posture. To do so, equipment prepared for quick deployment or prestaged must be available near where paratroopers and amphibious personnel are likely to deploy.

Fight Like You Train

The RDF should have a rotation system like that of U.S. MEUs, which maintain subordinate units on a 15-month cycle, because the current JSDF training system makes it difficult to improve or even sustain readiness for its anticipated operations.⁶ To be prepared to respond immediately to any contingency, there must be a clear distinction between periods of intensive training and periods of alert-to-respond for the RDF’s component units.

A lack of integrated transport support from the JASDF and JMSDF limits opportunities to rehearse large-scale airborne and amphibious operations. The Japan Ground, Air, and Maritime Self-Defense Forces must jointly develop sufficient capacity to deploy battalion- and regimental-sized rapid-deployment forces to the remote southwest islands. To this end, the three elements of the JSDF should wargame together and with various ministries, agencies, private think tanks, etc. Out of this must come concrete requirements for the transportation and logistical support necessary for NEOs and rapid-deployment operations in the anticipated contingency. In addition, necessary equipment (howitzers, antitank missile vehicles, etc.) and supplies should be prepared and positioned appropriately to speed the deployment process. This would allow organized combat power to move quickly—not only to the southwest islands, but also throughout Japan.

However, this can work only if a rapid-deployment standby rotation system is established. The 1st Airborne Brigade’s battalions and the ARDB’s regiments should emulate MEU and U.S. Army Airborne force rotations, alternating subordinate units between demanding training and standing by for contingencies.

Because the backbone of Japan’s concept for self-defense is coordination with its ally, the United States, Japan’s RDF must be able to match the deployment speed of the U.S. Marine Corps in littoral areas.⁷ The III Marine Expeditionary Force (MEF)—including the 3d and 12th Marine Littoral Regiments, the 1st Marine Aircraft Wing, and many other elements—is deployed to Japan and would be the principal U.S. “stand-in force” in a conflict. It also would likely be called on to assist Japan were Japanese territory invaded or captured. 

The revised training cycle should expand to include not only JMSDF and JASDF elements, but also U.S. forces, particularly the 31st MEU, the Marine littoral regiments, and the U.S. Air Force 374th Airlift Wing and its C-130Js. As former Commandant of the Marine Corps General David H. Berger described it, forces operating in littoral areas—remote islands, in Japan’s case—must be agile, and they require a true partnership among allies and partner nations.⁸ Training together can improve the interoperability of JGSDF and U.S. forces while Japan, as the host nation, can help the Marine Corps adapt to the Japanese operational environment—which would be extremely important should the forces need to defend the Japanese homeland in the future.

Overcoming Obstacles

It is possible that changes to the readiness system could create a burden on JMSDF ships, JASDF aircraft, and bases for each—both components have many missions, making it difficult to concentrate support only on the Rapid Deployment Force. But the total number of units that would comprise this force would be limited, so the burden should be manageable in the near term. Further, the JGSDF has already begun taking action to complement the functions of the JMSDF, which is suffering from a shortage of personnel and naval vessels, by establishing a new small-transport-vessel unit.⁹ In the future, as the JMSDF and JASDF concentrate their resources on core functions, the JGSDF, which has more personnel, will shoulder the burden of common functions by growing its landing craft and transport aircraft units.

Budget managers might note that the distribution of extra equipment and supplies is inefficient. This is plausible—maintaining a rotation system for the RDF could be expensive, which could increase the burden on conventional units and reduce overall defense capabilities. However, the JGSDF already maintains the necessary units, and the amount of prepositioned equipment required is only that needed for the initial stages, before larger forces arrive. An exorbitant budget therefore should not be necessary. Even if equipment and supplies are not prepared in advance, positioning the RDF appropriately as the situation deteriorates—but before conflict erupts—would reduce or eliminate the difficulty.

In addition, budgeters might be concerned that joint deployment training with U.S. forces would be expensive and not cost-effective to conduct repeatedly. And planners could note that joint deployment with U.S. forces on remote islands is an extremely challenging exercise. But full preparation for the most probable threats should be implemented, even if the cost is high.

And the good news about all the potential expenses is that the Japanese government has acted to double the defense budget—raising it to the equivalent of 2 percent of GDP, allowing the JGSDF to allocate a portion of its budget to the reserve fund.¹⁰ The JGSDF should use the increase to strengthen the RDF’s capabilities to maximize the value of that allocation.

The most important thing is to let an enemy planning an invasion know that the JGSDF can deploy an organized combat force quickly at any time.

Improving Flexibility

The JGSDF must become a more flexible force to deter future wars and defend the nation when necessary. An enhanced Rapid Deployment Force would be an important step in that effort to protect national security. An improved readiness structure and upgraded training system would allow the RDF to be more focused on its mission. Better logistics and prepositioned equipment would enhance its capacity to deploy quickly and with little notice.

This force would boost its capabilities and interoperability through more frequent and complex joint training with U.S. forces in Japan, especially the U.S. Marine Corps. Taking the ARDB and 1st Airborne Brigade from rapidly deployable forces to a true Rapid Deployment Force would be time-consuming and costly—but essential to deterring war and defending Japan. Some contingencies are bound to become operations, and the JGSDF must prepare for them seriously.