Japan’s New Security Posture and Its Implications for Taiwan

In 2021 talk of conflict over Taiwan has grown to an unprecedented level, both in Japan and the United States. Bilateral plans for responding to Chinese coercion have drawn attention, even if “strategic ambiguity” remains the official US position. While much of the coverage has centered on China’s behavior and on US debates over how policy may change to Taiwan, Japan’s military preparations warrant close attention, too. This article focuses on the details of the strategic reorientation to what Japanese call the Southwestern region. The challenge there is not only conflict over Taiwan but also a serious spillover of military threats to the territorial land, sea, and air spaces of the Southwestern region including the Senkaku Islands. How Japan’s Self-Defense Forces (JSDF) are preparing for a Taiwan crisis cannot be easily divorced from its preparations for a conflict over islands which China also claims—as part of reunification moves toward Xi Jinping’s “China Dream.”

Admiral Philip S. Davidson, Commander of the U.S. Indo-pacific Command, testified before the Senate Armed Service Committee on March 9, 2021, pointing out that “the PRC represents our greatest strategic threat. Its rapidly advancing capabilities and increasingly competitive posture underscore its drive to become a regionally dominant, globally influential power.”¹ The admiral added that “Taiwan is clearly one of their ambitions” before 2050 and that he thinks “the threat is manifest during this decade, in fact in the next six years.” China’s military capabilities have been drastically improved in the last couple of decades and their activities around Japan have become more and more assertive for Japan, particularly in the East China Sea, which Japan’s Southwestern region divides from the Western Pacific. To avoid the situation about which the admiral is worried Japan along with the United States will have to keep trying to improve the security and defense posture around Japan, the Southwestern region in particular.

The sections below (1) offer an overview of Japan’s defense posture and geo-strategy, (2) explain the strategic significance of the Southwestern region, (3) draw a connection to Japan’s China policy, (4) point to newly introduced defense systems, (5) trace the evolution of the JSDF posture in the area, and finally (6) go into more specifics on the role of the Japan-US alliance in the Southwestern region. The article concludes with coverage of the importance of Japan’s improved defense posture for deterrence of an actual conflict. 

Japan’s Defense Posture and Geo-strategy
In August, 1994, the Prime Minister’s Advisory Group on Defense Issues chaired by Higuchi Kotaro pointed out that Japan played a certain role for global security during the Cold-War period as follows:
Japan’s mission was to defend the country based strictly on the right of self-defense. In light of its geographical position, however, Japan naturally played an important role in the anti-Soviet strategy of the Western bloc.²

The above-stated strategic significance in the context of global security was gone as the Cold War ended. Japan was, therefore, required to answer the question of what responsibilities it should assume within the international community for the peace and stability of areas where it has a stake, such as Southeast Asia and the Middle East. This left Japan struggling to expand the scope of its overseas operations including the UN peacekeeping operations, but the question was not definitively answered. At the beginning of the 2020s, it is even more urgent for Japan to return to the basic question of what kinds of capabilities are required for peace and stability in the areas surrounding Japan. In other words, as a rising China has proved militarily assertive particularly in the East and South China seas, Japan needs to rebuild its security and defense posture to match the drastically changing strategic environment.   

Strategic Significance of the Southwestern Region
The Southwestern region stretches from the south of Kyushu to Taiwan, consisting of a 1,200 km long strategic archipelago that divides the East China Sea and the Western Pacific. The expanded area with Taiwan and the Philippines comprises a strategic archipelago that China calls the first island chain for its A2AD (Anti-Access/Area Denial) capabilities, while being a key zone for the US with a chain of its allies and partners. In the Southwestern region, there are nearly two hundred islands bigger than 0.01 square kilometers of which 70 are inhabited with around 1.6 million in population.³ The widest gap between the islands is between Okinawa and Miyako Islands, amounting to 260 km. Other gaps are generally around 100 km wide.

It is extremely scary to imagine the situation where control over the Southwestern region is taken from Japan as once happened at the end of WWII. Allied forces led by the US landed on the Philippines in October 1944, followed by amphibious landing operations on Iwo Jima in February and on Okinawa in April 1945. After these battles, Japan’s sea lines of communication were totally cut and control over the air space around Japan was in the hands of allied forces. Not only military operations by the army and navy but also minimum economic activities necessary for the nation’s survival became nearly impossible.

Such a situation would not only result in challenges casting doubt on Japan’s very survival but also lead to serious deterioration in the overall strategic balance for Japan, the US, and their allies and partners in the area from the East and South China seas through the Malaccan Strait to the Indian Ocean. The side that takes control of the Southwestern region from Japan would have free access to the Western Pacific and the capabilities to deny Japan access to the East China Sea and to the Southwestern region itself. Furthermore, Taiwan and the Philippines, each with particular strategic importance as a gateway at the entrance to the South China Sea, would also be affected seriously. If either were to be under China’s control, the strategic balance in the South China Sea would drastically change. The sea lines of communication there are one of the most important arteries for the world’s economy, and Japan’s lifeline would become unavailable. This would also cause difficulty in realizing the “Free and Open Indo-Pacific” (FOIP), which has been proposed by Japan and the US and emerged as the core of their reconceptualization of Asian security.

Japan’s China Policy and Defense Posture in the Southwestern Region
The strategic significance stated above is an important factor when Japan develops its policies vis a vis China. The situation in the East China Sea has seriously deteriorated, particularly since 2012 when the Government of Japan assumed ownership from the private sector. Japan and China have been in a highly tense situation for the last decade. Although Japan has kept exercising administrative control over the Senkaku Islands and the surrounding territorial air and sea space, China has repeatedly sent its official ships into the territorial waters since 2012. In the year from September 2020, China’s coast guard ships violated the territorial waters around the Senkakus nine times per month for an average of four days and navigated in the contiguous zone for 335 days. While both Japan and China have been cautious about escalating to the level of military to military confrontation and have restrained from sending military vessels and aircraft into the territorial space, a PLA Navy’s surface combatant entered the contiguous zone for the first time in June 2016 followed by a second incident in January 2018 with a submarine and a surface ship.⁴

With such tense relations, as outlined above, Japan’s China policy has been a mixture of soft and hard approaches, including pursuing areas for mutual cooperation, while making it clear it will protect whatever it should protect. The Diplomatic Blue Book 2021 explains this point as follows:
The relationship with China, the neighboring country across the East China Sea, is one of Japan’s most important bilateral relationships, and the two countries have close economic relations, as well as people-to-people and cultural exchanges. Stable relations between Japan and China are important not only for the two countries but also the regional and global communities. In the meantime, as there remain pending problems, Japan needs to keep arguing for what is required and strongly requesting China’s compliance through high level meetings between the leaders and foreign ministers.⁵

As an example, at the end of 2019, Prime Minister Abe Shinzo just before a summit meeting with President Xi Jinping in China, reportedly said “we’d better tell China whatever we believe we need to say.”⁶ According to the record of the meeting, while the prime minister raised positive issues such as Xi’s visit to Japan as a state guest and a bilateral approach towards the “era of New Japan-China relations,” he (1) confirmed with Xi that the two sides “will advance maritime security initiatives, including concrete initiatives under the Maritime and Aerial Communication Mechanism” between military and law enforcement organizations of the two countries, (2) “strongly requested China’s positive responses to the East China Sea issue, including the waters surrounding the Senkaku Islands,” and (3) “sought the exercise of self-restraint by all parties” concerning Hong Kong matters while requesting China “to provide a transparent explanation of the human rights situation in the Xinjiang Uygur Autonomous Region.”⁷

Newly Introduced Defense Systems
In addition to diplomatic activities, the recent changes in Japan’s defense posture are understood to have been responses to the rise of China. One of the featured policies of the National Defense Program Guidelines and Mid-term Defense Program (FY2019-2023) adopted in 2018 is to enhance capabilities for island defense with the introduction of new systems suited for such a mission and for improving the posture of force deployment in the Southwestern region.⁸ Among the newly introduced systems, there is a plan to establish capabilities to employ light aircraft carriers by modifying two currently existing helicopter carriers to enable them to operate F-35B fighter jets that have short-take off and vertical landing capabilities. In December 2018, the National Security Council made a decision to increase the number of F-35s being procured from the original 42 F35As to 147 while substituting 42 F-35Bs as part of the total.⁹

The plan for light aircraft carriers is designed to mitigate one of the problems of the defense posture in the Southwestern region, a shortage of operational airfields. Currently the Naha JSDF base on the main island of Okinawa is the only active JSDF airfield, while Shimoji airfield next to Miyako Island is expected to be available in case of emergencies. There is a plan to build an alternative airfield on Mage Island located at the northern tip of the Southwestern region. It is designed for multiple purposes, including the US Navy’s carrier landing practice for American jets temporarily deployed to Marine Corps Air Station Iwakuni and Japan Self-Defense Forces (JSDF) air training. This leaves a posture of one active and two alternate airfields, which falls far short of projected needs when considering the wide scope of the Southwestern region, which is equivalent to the size of Japan’s main island, Honshu. While limited, the Japan Maritime Self-Defense Force (JMSDF) aircraft carrier capabilities will help to fill the shortfall of operational bases.

Programs for newly enhanced capabilities relevant to island defense include (1) increased air transportation capabilities with newly introduced aircraft such as C-2 cargo airplanes with four times longer range and three times larger payload than its predecessor C-1, and V-22 tilt-rotor aircraft with vertical takeoff and landing capabilities the same as a helicopter in addition to its long range and cruising airspeed similar to fixed wing cargo airplanes; (2) increased sea lift capabilities by the activation of a jointly operated sea lift command with a medium-size logistic support vessel (2,000 tons) and four small-size transport vessels (several hundred tons); and (3) long-range strike capabilities by introduction of air to surface missiles such as the Joint Air-to-Surface Standoff Missile (JASSM) with a range over 370 km or over 800 km, and research and development efforts for high velocity gliding missiles for island defense.¹⁰

While the above stated long-range strike capabilities have always been discussed in a context of capabilities to strike targets in the enemy’s territory, longer range fire has another important advantage for island defense. Considering that gaps between major islands in the Southwestern region vary form 150 km to 250 km, missiles with 300 km range if appropriately deployed may provide cover over most of the islands and gaps between them. If Japan Air Self-Defense Force (JASDF) fighters are equipped with air-to-surface missiles with a range of 800 km, they can cover all the islands in the area from airspace over Okinawa Island. Long spears can be pointed to both sides rather than for depth to cover a wide area of responsibility for more effective defense operations.

Evolution of JSDF Posture in the Southwestern Region
The Ministry of Defense has kept working hard to enhance the defense posture in the Southwestern region as it used to be extremely weak for this vast area of responsibility. According to Defense of Japan 2011, major JSDF units deployed in the area were Japan Ground Self-Defense Force (JGSDF) 15th Brigade, JMSDF 5th Fleet Air Wing, and JASDF Southwestern Composite Air Division with strength of a couple of thousand. While those major units are all located on the main island of Okinawa, there used to be JASDF radar sites on only three other islands, Okinoerabu, Kume, and Miyako islands. As the Southwestern region stretches 1,200 km from the south of Kyushu to Taiwan, the posture was simply too thin. If one looks back at the fact that the JSDF deployed 107,000 service members to Iwate, Miyagi, and Fukushima prefectures during its disaster relief operations after the East Japan Great Earthquake in 2011, it is obvious that a significantly strengthened posture was needed.

In the past it was considered extremely difficult to strengthen the JSDF posture in the Southwestern region, particularly within Okinawa Prefecture, for several good reasons.: (1) Okinawans were directly involved in ground combat in the rare exception during WWII–memory of the war remains far more vivid than in the rest of Japan; (2) Okinawan society has been negatively affected by US bases located in the most densely populated southern part of Okinawa Island; (3) Tokyo sacrificed and abandoned Okinawa to gain time to prepare for battles to defend the main islands of Japan at the end of WWII; and (4) Tokyo abandoned Okinawa for the second time when Japan regained sovereignty without Okinawa in 1950.  

At the same time, threat perceptions among people in Okinawa are more significant than the rest of Japan as China and North Korea are geographically closer than to other areas. China’s maritime activities, including those of the coast guard and PLA Navy, as well as fishermen have posed a visible threat to people involved in the fishing business in the Miyako and Ishigaki areas as their activities are directly affected. In 2012 when North Korea launched a missile over Okinawa Prefecture to offshore Philippines, people in Miyako and Ishigaki islands along with Okinawa Island showed higher tolerance towards deployment of JSDF ballistic missile defense units and chemical protection units there.

Under the second Abe administration born in 2012, the JSDF posture in the Southwestern region has been drastically enhanced. Following the activation of a watch station of the JGSDF on Yonaguni Island, the westernmost island in the area, newly activated JGSDF units were deployed to Amami Oshima in Kagoshima Prefecture and Miyako Island, 250 km southwest of Okinawa Island in 2019. In the spring of this year, the Government of Japan decided to activate a new unit on Ishigaki Island.¹¹ JGSDF units deployed to those islands are basically the same in organization with an infantry heavy security unit, a surface-to-air missile unit and surface-to ship missile unit with the strength of 500-700 persons.¹²

While relatively small in size, the units on the three islands have strategic significance. They along with the already deployed units on Okinawa Island will provide a posture where sets of anti-air and anti-ship capabilities are positioned on the key locations within the Southwestern region at intervals of 150 to 300 km. Units deployed on Miyako and Ishigaki islands, for example, will have aircraft and ships possessing anti-air and anti-ship missiles within tens to a hundred plus km radius from the two islands. This posture while providing a local umbrella against air and maritime threats will play an important part in joint efforts of the JASDF and JMSDF to achieve air and maritime control. For a long time, land combat capabilities have been discussed as the last resort to protect Japan’s territory against enemy forces after air and maritime defensive efforts. In the context of the defense of the Southwestern region, land forces deployed on remote islands should be regarded as an advance guard or combat outposts for the fight over air and maritime control.   

Japan-US Alliance and Defense of the Southwestern Region
The new role of the forward-deployed ground component for air/maritime control, noted in the last part of the previous section, is now being shared between the JSDF and US forces in the context of allied operations.

U.S. Navy and Marine Corps’ new operational concept
In April 2021, General David Berger, commandant of the U.S. Marine Corps, announced the Marines’ reorganization plan, releasing “Force Design 2030 Annual Update.”¹³ This document aims at drastic changes in the Marine Corps’ operational concept and organization departing from power projection by an amphibious assault landing such as the one on Normandy in 1944. The new concept requires marines to contribute to the navy’s quest for sea control by advancing distributed bases with anti-ship capabilities to remote islands or shores located in contested areas. The new operational concept is titled “Expeditionary Advanced Base Operations (EABO).”¹⁴

The “Advanced Base Operations” part has a predecessor born during the inter-war period. One of the most serious problems of War Plan ORANGE designed for possible war against Japan was the absence of a defensible American base system in the Pacific. Operation Plan 712D “Advanced Base Operations in Micronesia” drafted by Major Earl H. Ellis was to solve this problem by seizing defended islands by amphibious assault landing operations. According to Major Ellis’s plan, “naval gunfire and air strikes would provide the fire superiority that conventional artillery could not provide while waves of landing craft brought infantry, machine guns, light artillery, and tanks to the beaches.”¹⁵

EABO is similar to Ellis’s plan in supporting the navy’s operations. At the same time, EABO differs from amphibious assault landing operations conducted under decisive air and maritime superiority gained prior to the landing, placing emphasis on capabilities to operate in contested areas. In support of fleet forces operating to gain air and maritime superiority, marines are required to advance small-sized, scattered, and temporary bases that are equipped with high mobility along with anti-ship fire power, local air defense, and logistical support for aircraft.

To implement the concept, three regiments stationed in Hawaii, Okinawa, and Guam under the command of the Third Marine Expeditionary Force (III MEF) will be reorganized into Marine Littoral Regiments (MLR). The MLR with 1,800 to 2,000 marines and sailors consists of a Littoral Combat Team organized around an infantry battalion along with a long-range, anti-ship missile battery, a Littoral Anti-Air Battalion for air defense, air control, and forward rearming and refueling, and a Littoral Logistics Battalion providing support for MLR.¹⁶ With new organizations such as MLR, the U.S. Marine Corps is aiming at capabilities to “fight at sea, from the sea, and from the land to the sea; operate and persist within range of adversary long-range fires.”¹⁷

US land components’ interest in the Southwestern region
In addition to marines stationed in this area including Okinawa, the U.S. Army has shown greater interest in operations to defend remote islands. In July 2021, as part of the annual bilateral exercise “Orient Shield,” it deployed an air defense unit with PAC-3 missiles to Amami Oshima from Okinawa and conducted bilateral training with the JGSDF 8th Antiaircraft Artillery Group with Chu-SAM anti-air missiles deployed from Hyogo Prefecture.¹⁸ During this exercise, the 17th Field Artillery Brigade stationed in Washington state deployed a unit of High Mobility Artillery Rocket System (HIMARS) to the Yausubetsu firing range in Hokkaido and conducted a live fire exercise with a JGSDF artillery unit equipped with the Multiple Launch Rocket System (MLRS). While they have similar capabilities for shooting long-range rockets, U.S. HIMARS is light enough to be loaded on a C-130 medium-size cargo plane and has higher mobility and longer range on land than the MLRS; thus, it is suited for rapid deployment to remote islands. It can shoot Army Tactical Missile System (ATACMS) that has potential anti-ship capabilities.¹⁹ The U.S. Army recently has shown growing interests in anti-ship capabilities and operations in the Pacific theater.²⁰ The recent deployment of PAC-3 to Amami Oshima and participation of HIMARS in bilateral training are signs of that.

The marines’ interest in island operations in the context of EABO implies their commitment to the defense of the Southwestern region. III MEF headquartered in Okinawa in particular through discussions with JSDF leaders has shown its determination to stay in this area as Marines describe III MEF as a “stand-in force” that persists in operations under the certain influence of a hostile military such as long-range fire power. Demonstrating its interest in operations in Japan, III MEF used a media opportunity last April for a demonstration of an exercise using Japanese as the language for communications.²¹ As the operational concept of EABO requires marines to operate as the advance guard of the navy in the archipelago from Japan’s Southwestern region to the Philippines, their deployment onto islands located in the Southwestern region naturally falls within this scope.

Roles and missions of Japanese and US land components
The mission and organization of MLR, the marines’ new regiment, and JGSDF’s new posture in the Southwestern region explained earlier are similar concepts. This similarity can be found in their tasks to contribute to the efforts of air and maritime forces for air and maritime superiority, and their organizations that include built-in anti-air and anti-ship capabilities. Differences are in their ways of deployment. While MLR with its superb agility is designed to rapidly deploy to the area of operation, JGSDF units stationed on islands such as Miyako and Ishigaki Islands are deployed in their defense positions in peacetime and operate and persist as first responders until reinforcement comes in contingencies. Follow-on forces in such a case include the 1st Amphibious Brigade and the 1st Airborne Brigade for rapid deployment followed by mobile divisions and brigades that have higher mobility with lighter equipment. The forward-deployed forces will provide local air and maritime cover for advance of aircraft and ships.

To deter any military contingency in the Southwestern region, the defense posture by JSDF and U.S. forces is the key. In this context, U.S. MLRs may have a significant role to rapidly deploy their capabilities between already deployed JSDF forces to fill gaps and to extend JSDF’s western wing to the Philippines. This enhanced posture can provide the two countries’ air and maritime forces with cover for their operations in the East China Sea, thus strengthen the defense posture in the Southwestern region of Japan. If the U.S. Army shows its capabilities to deploy land forces such as HIMARS as stated earlier, deterrence will have more credibility. 

For the JSDF, it is especially important to demonstrate the determination to defend Okinawa. As stated above, Okinawa was sacrificed to gain time to prepare for defensive operations on Japan’s main islands at eh end of WWII. In November 1944, the 9th Division, one of three divisions assigned for the defense of Okinawa, was transferred to Taiwan. The 32nd Army in charge of the Southwestern region came to face extreme difficulty in defending Okinawa and protecting citizens there. The battle of Okinawa started by a US amphibious landing on April 1, 1945 resulted in a tragedy where citizens were involved in combat operations and caused over 120,000 deaths of Okinawans including 94,000 civilians. This history alone proves that determination to defend Okinawa and to protect civilians is a must for Japan.

Conclusion
Any event in which the US and Japan are involved in military operations against China for air and maritime superiority in the Southwestern region would cause extremely serious damage not only for the two allies but also for China. Former deputy director general of the national security secretariat Kaneharu Nobukatsu clearly points out that “a Taiwan contingency is a contingency of Japan itself” as “Sakishima Islands (consisting of Yonaguni, Iriomote, Miyako, Ishigaki and the Senkaku Islands) ranging from just 100 km away from Taiwan would be physically involved” in any such contingency.²²

In terms of security threats in geographical proximity, the Korean Peninsula has been another concern for Japan as there are high tension between the North and South while North Korea’s nuclear and missile programs have posed threats to Japan. However, there is a significant difference between Korea and Taiwan. South of the 38th parallel, there is a formidable deterrent posture consisting of ROK armed forces, one of the best equipped militaries in the world with some six hundred thousand young Koreans in uniform supported by one of the world’s largest economies along with US forces deployed on and around the peninsula, providing Japan with a secure western flank since the 1950s. In comparison, Japan has nothing for protection against a military spillover from Taiwan on its southwestern flank. To avoid such a situation, it is essential to establish and maintain mutual deterrence with a state of stalemate where neither side could force its will on the other by defeating it while neither side would lose decisively.

What Japan should immediately do for this is to demonstrate its determination to protect its territories by deploying JSDF elements to major islands in the Southwestern region. In the meantime, it is extremely effective to demonstrate US capabilities to advance its navy and marines to the concerned areas based on the operational concept of EABO while showing the possibility of deploying army and air force units from outside. Such capabilities significantly increase uncertainty for the opponent; thus, they provide more credible deterrence.