On June 8, 2018, Japan and China launched a communication mechanism between their defense authorities to avert accidental clashes in the air and on the sea. This is a huge achievement for the two countries, but it still leaves a major outlier, which has direct security relevance for Japan. In fact, the only remaining neighbor who cannot communicate smoothly with other defense authorities is Japan’s neighbor to the southwest: Taiwan.

Six Neighbors

Japan is an island country surrounded by the sea on all sides and faced with six neighbors across those seas. Counterclockwise from the north, Japan’s neighbors are Russia, the Republic of Korea (ROK), China, Taiwan, the Philippines and the Northern Mariana Islands, and they all border Japan’s Exclusive Economic Zone (EEZ).

The EEZs of the Northern Mariana Islands and Japan touch each other near the southeast of Minami-Iou-toh in Japan’s Ogasawara Islands. The Northern Mariana Islands are a Commonwealth of the United States. Therefore, the U.S. Armed Forces and Coast Guard are in charge of the defense and maritime law enforcement of the Northern Mariana Islands. The remaining five neighbors hold reasonable capability for naval power and maritime law enforcement necessary to control their own territorial waters and EEZ.

Since August 1945, Russia has illegally occupied Japan’s Northern Territories (which Russia calls the Southern Kurils), including Kaigara-jima Island located approximately two nautical miles off Cape Nosappu of Hokkaido. As a result, the territorial waters and EEZ which both countries claim overlap, yet Japan and Russia have not concluded a peace treaty. However, Japanese and Russian defense and law enforcement authorities have had various exchanges and communications, including joint exercises. Additionally, the Incidents at Sea agreement between Japan and Russia, signed by both in 1999, has become an effective means for accident prevention and has helped build confidence on both sides.

The Republic of Korea has, from Japan’s point of view, illegally occupied Takeshima (known by the South Koreans as Dokdo) in the Sea of Japan since 1953. This created another situation where the territorial waters and EEZs of both countries overlap. Additionally, the ROK claims the continental shelf in the East China Sea. However, the ROK is allied with the United States, and this alliance has helped to build various channels and frameworks between both Japanese and Korean defense and law enforcement officials and has included joint exercises.

The Philippine EEZ overlaps with Japan’s Sakishima Islands near Okinawa. The borders of the two countries’ EEZ are based on the principle of a median line as defined in the United Nations Convention on the Law of the Sea (UNCLOS). Like the ROK, the Philippines is allied with the United States. This alliance has also helped to build relations on many levels between Japanese and Philippine defense and law enforcement officials. For example, the Philippine Navy has received aircrafts from Japan Maritime Self-Defense Force (JMSDF), and the Japan Coast Guard (JCG) has provided patrol vessels to the Philippine Coast Guard.

China insists that almost all of the East China Sea is within their EEZ. Their excessive claim includes the continental shelf, and China has been pushing forward to develop undersea resources for themselves, despite Japan’s rights and their own public statements, such as the Joint Press Statement for Cooperation between Japan and China in the East China Sea in 2008. China also claims the Senkaku Islands as their own territory and deploys fishing vessels and Coast Guard ships to operate in and around the Senkakus. While China has not been transparent in the East China Sea, it did agree to a framework in 2018 for preventing collisions between Japan Self-Defense Forces (JSDF) and People’s Liberation Army (PLA). Despite the more recent lack of transparency, past efforts at normalization of Sino-Japan relations in 1972 created opportunities for exchanges and communicating intent at the minister level and between JSDF and PLA units and individuals, including joint exercises. These exchanges continue today. For example, some JSDF officers studied in the PLA National Defense University, and some PLA officers studied in the National Institute for Defense Studies in Japan, which is the equivalent to the National Defense University. Additionally, many JSDF and PLA officers exchange with each other annually through the support of non-governmental organizations.

Only Taiwan remains as the neighbor which shares a border with Japan, but has no communication framework linking Taipei and Tokyo.

Un-Transparent Power, Taiwan Military Capability

Almost all Japanese people feel a kinship with Taiwanese people. But Japan does not understand Taiwanese military powers. Japan sees no Taiwan military, hears no Taiwan military and speaks no Taiwan military.

Generally, Japanese citizens believe that Taiwan is their friendliest neighbor. Also, Taiwan citizens recognize Japan as the best friend in the world. But, after normalization of Sino-Japan relations over forty-five years ago, Japan-Taiwan relations were downgraded, and currently only exist on an informal basis. Therefore, JSDF and Taiwan armed forces have not had any communication with each other.

Taiwan’s armed forces are not members of any multilateral framework involving a global and regional defense/military community. The multilateral framework of defense/military communities facilitates interactions from the minister level, such as the ASEAN Regional Forum (ARF), the ASEAN Defense Ministers Meeting Plus (ADMM-Plus), to chief of service level, such as the International Seapower Symposium (ISS), the Western Pacific Naval Symposium (WPNS), and offers various practical opportunities, not only to senior civilian and military leaders but also junior sailors and soldiers to develop mutual understanding. For example, though JSDF officers have few chances to meet with PLA officers, both officers can learn from each other through the experience of joint exercises and joint activities under ADMM-Plus, ARF or WPNS. However, Taiwan’s nonmembership in these associations or mechanisms prevents their armed forces from participating.

Since Taiwan is absent from modern global frameworks, the JSDF does not have any exchange programs or relations with Taiwanese armed forces. As time has passed, Japan has forgotten Taiwan’s military capabilities. Even the global community does not know Taiwan’s military capability.

Democratic Peace Theory is not a Panacea

Just because the Japanese and Taiwanese people are friendly toward one another, it can never be asserted that armed conflict will not occur between Japan and Taiwan. Even though both Japan and Taiwan are advanced democratic bodies, this also does not mean that armed conflict will not occur between them.

Japan is an allied partner of the United States, and Taiwan has a special relationship with America as well. And, while almost all of the Japanese feel closeness with the Taiwanese, and believe Taiwan is their most friendly neighbor, it is clear that Taiwan’s interests do not completely align with Japan’s national interest. Taiwan claims the Senkaku Islands as their own territory, as does the People’s Republic of China. Taiwan’s territorial waters, EEZ and Air Defense Identification Zone (ADIZ) overlap with Japan’s.

It is inevitable that some kind of problem or friction will occur between neighbors whose borders touch. Looking back over our modern history, friction has occurred between friends and allies. And friction can sometimes lead to armed conflict. Even among the members of the NATO, a strong alliance of advanced democratic countries, conflicts have occurred in the past—for example, the Cod Wars between the UK and Iceland from 1958 to 1976, and a dogfight over the Aegean Sea between Turkey and Greece in 2016.

Indeed, various episodes of friction have nearly sparked armed conflict between Japan and Taiwan several times in the past. For example, during KMT leader Ma Yingjeou’s administration, a Japanese Coast Guard vessel collided with a Taiwanese fishing boat off the Senkakus, which Taiwan claims for itself (referring to the islands as Diaoyutai). In response, Taiwan’s Premier, Liu Chaoshiuan, warned: “Taiwan does not hesitate to threaten war with Japan.” And in September 19, 2012, Ma Yingjeou ordered Taiwan’s Navy and Air force to “Prepare for defending Diaoyutai [Senkakus].”

Even if there is no aggressive intent, neighbors may violate the sovereignty of their neighbor by mistake. For example, in July 2012, a Taiwanese Navy’s destroyer (DDG-1802), which was conducting an exercise, approached by mistake Japanese territorial waters (these waters were also considered by Taiwan to be Japanese territorial waters).

Even today, Taiwanese President Tsai Ingwen and her administration have not changed the policy concerning the Senkaku Islands.

Implications

The lack of communication with Japan’s southwest neighbor, Taiwan, creates a “Missing Link” in Japan’s border security and the most vulnerable frontline. If a conflict arises on any of Japan’s borders, Japan and its other five neighbors can manage the crisis immediately by using established communication channels to prevent the event from escalating into a crisis. However, if an incident occurs between JSDF and Taiwan armed forces, both sides lack the necessary tools to manage an unexpected crisis. Further complicating the issue would be the intervention of China. In fact, despite Taiwan repeatedly stating that it will not cooperate with China regarding the Senkaku issue, China continues to appeal to Taiwan for joint coordination regarding the islands.

In order to resolve the “Missing Link,” we have a few recommendations.

First, Japan must develop an understanding of the capabilities of Taiwan’s armed forces and begin to find ways to improve security on Japan’s southwest border.

Second, the regional defense / military community should welcome Taiwanese armed forces as observers—similar to the APEC model. Taiwan is a member of the Asia-Pacific Economic Cooperation (APEC) as one of the region’s “economies,” just like Hong Kong. For example, WPNS should invite Taiwan’s navy as a “naval power,” because Taiwan’s naval forces in the South China Sea might become important actors. Under the multilateral framework, Taiwan’s armed forces have to strive for transparency with other members.

Third, JSDF and Taiwan armed forces can open some form of communication in order to prevent an unplanned encounter from creating friction on their shared borders. For example, in 2013 both Japanese and Taiwanese maritime law enforcement authorities opened up a small communication channel under the Japan-Taiwan fisheries agreement. Though, this agreement is not a formal diplomatic agreement, between the Interchange Association of Japan (present name, Japan-Taiwan Exchange Association) and Taiwan’s Association of East Asian Relations (present name, Taiwan-Japan Relations Association). Both associations also signed a Search and Rescue agreement in the same manner. Under this nongovernmental agreement, both Japanese and Taiwanese maritime law enforcement officials have established a communication channel for crisis management. Both defense authorities can look for opportunities to make similar communication channels in order to avoid escalation during an unexpected incident.

For Japan’s border security, and the resilience of the stability in the region, the “Missing Link” is the clear and present danger. Japan has to resolve this “Missing Link” as soon as possible before any friction occurs.

For the United States of America, any friction between Japan and Taiwan will further complicate the U.S. security posture in the region, stress the stability in the Indo-Pacific and have an overall negative impact to global security. The United States must work with its ally, Japan, and its friend, Taiwan, to resolve this “Missing Link” before any friction has unintended consequences.

Capt. Katsuya Yamamoto is the Japan maritime Self-Defense Force (JMSDF) Liaison Officer and International Military Professor at the U.S. Naval War College. Capt. Adam M. Aycock is a researcher at the U.S. Naval War College’s Institute for Future Warfare Studies. The opinion expressed here are the authors’ alone and do not reflect the assessments of the JMSDF, U.S. Navy, or the U.S. Naval War College.