A Japanese Perspective

"US-ROK-Japanese Trilateral Security Cooperation"


In the mid-1990s, when Japan and the United States redefined their alliance and revised the “Guidelines for Defense Cooperation between the United States and Japan” to match the new set of international security challenges that arose after the end of the Cold War, trilateral security relations among the United States, the Republic of Korea (ROK), and Japan were substantially improved with particular focus on the three countries’ efforts to deal with the threat posed by North Korea’s nuclear and missile programs as well as its conventional military provocations. In recent years, however, these trilateral relations have been stagnant mainly because ROK-Japanese relations have been tense due to the reemergence of problems, including the territorial dispute over the Dokdo/Takeshima Island, the “comfort women” issue, and other history-related issues. These issues enflamed nationalist sentiments within the two countries and heightened antagonistic feelings against each other. As North Korea has become more and more provocative demonstrated by its recent nuclear and missile tests, the situation in the region is highly tense and requires much closer cooperation among the three countries along with robust ROK-US and Japan-US alliances. China’s rise too requires the three countries to have closer, deeper dialogue to coordinate their respective policies to steer China towards cooperative, if competitive, and constructive relations with the rest of the world. The recent development in the bilateral relationship between the ROK and Japan is a promising start with the first ever summit meeting between Prime Minister Abe Shinzo and President Park Geun-hye in November 2015 and the following foreign ministry dialogue to settle bilateral problems including the “comfort women” issue. This political leadership toward a better relationship should be followed by various efforts, as proposed below.


Proposed Efforts Aimed at Triangularity

First, the two countries should start acknowledging their mutual dependence in various fields including national security as well as cultural and economic areas. In particular, Japan, including its public, should deeply understand and explicitly appreciate the fact that the ROK-US alliance has protected its western flank for more than half a century-a period exceptional in Japan’s history. Japanese strategic thinkers have always been concerned about the western flank because most of the battles between Japan and China (at times with their allies) since the seventh century have been fought on or through the Korean Peninsula. During the Battle of Baekgan (or Hakusukinoe in Japanese) in 663, Japan suffered total defeat in the southern part of the Korean Peninsula against the alliance of the Tang Dynasty of China and the Siila Kingdom of Korea. After that, the Yamato Court feared an invasion from Tang or Siila and started to establish the first ever defense system in the western part of Japan with frontier guards (sakimori), signal fire systems, and permanent fortifications. After the Meiji Restoration, Japan tried to secure its western flank at the expense of Korean sovereignty and national pride, which eventually led to its complete and decisive defeat in 1945. Since then, particularly after the ROK-US alliance successfully repelled North Korea’s aggression, Japan has enjoyed a perfectly secured western flank thanks to both the Korean and US militaries.


In addition, Korea and Japan should have a shared understanding that the ROK-US and Japan-US alliances are inseparable and interdependent for the security of both the ROK and Japan. As for the Korean Peninsula, the ROK-US alliance, on the one hand, directly deals with any contingencies on the peninsula that might easily spill over to Japan, and the Japan-US alliance, on the other, provides Korean and American troops with security in their backyard and logistical support as demonstrated in the 1950s. In fact, there was a time in the mid-1990s when Japan and ROK strongly promoted security cooperation due to the increasing necessity in dealing with the heightened tension over North Korea’s nuclear programs. Public diplomacy between the two countries during that period helped people deepen mutual understanding through track 2 dialogues. For example, the February 1999 issue of This is Yomiuri carried an article on a simulation over maritime crisis management focusing on cooperation between the ROK Navy and Japan Maritime Self Defense Force (SDF) in case of contingencies caused by North Korea.1 According to the article, academics, ex-government officials, and ex-military officers of the two countries had extremely deep and forward-looking discussions on naval cooperation to deal with threats posed by North Korea. A book entitled US-Korea-Japan Relations: Building towards a “Virtual Alliance” published in 1999 is another example.2


Second, the three countries should utilize the two alliances and trilateral cooperation as international public goods in regional and global contexts. Related to the previous point, the three countries share a common understanding of the importance of US political commitment to and military presence in the Asia-Pacific region for peace and stability in the region as well as the international community as a whole. Since sustainable stationing of US forces in Korea and Japan is essential to the US forward deployment posture, the Korean and Japanese governments have to make their best efforts to smoothly host US service members. For Japan, the plan for the realignment of US forces in Japan, including the relocation of the Marine Corps Air Station Futenma, should be implemented as soon as possible. In the meantime, the three countries’ armed forces are becoming more and more active in non-traditional military operations abroad, such as UN peacekeeping operations (PKO) and humanitarian assistance and disaster relief operations. Among a number of examples, assistance to the Philippines after Typhoon Haiyan in 2013 is noteworthy. While US marines demonstrated their high readiness with their prompt deployment followed by the SDF’s entry, Korean soldiers stayed in the affected area for a longer time to reconstruct the local community.3 The three countries should coordinate while cooperating with others for such international missions whenever it is possible and effective.


Third, the ROK, Japan and the United States should deepen security cooperation over the issues related to North Korean threats. In this context, it is crucially important for the three to thoroughly address differences in their threat perceptions based on geographical distance from North Korea as such differences may result in divergent policy priorities. The ROK, with its geographic proximity to North Korea, may give priority to maintaining the stability of the peninsula by avoiding armed conflict and preventing domestic chaos within North Korea. Japan puts a priority on dealing with North Korea’s long-range missiles and nuclear weapons through international efforts to prevent it from developing and deploying such missiles as well as pursuing its nuclear programs. Japan also places great weight on its own efforts to protect its population through ballistic missile defense programs. The United States along with the rest of the world seems to be pursuing a policy to prevent North Korea from further proliferating its nuclear weapons and missiles. In the long run, the three may strike a balance along with others in combining all of these goals, but they should be well aware of the differences in their short-term policy priorities. The bottom line is that different goals must be pursued in a manner that does not neglect others. For example, Japan may work hard to reduce the threat from North Korea’s missiles, that should not be pursued at the expense of other goals such as stability on the peninsula. In any case, no one should compromise with North Korea on its obligation to abandon its nuclear ambitions in return for gains on other policy goals.


Fourth, nuanced differences in China policies toward the three countries-particularly those between Korea and Japan-should be thoroughly addressed. In June 2015, on the fiftieth anniversary of ROK-Japan normalization, the Institute for International Policy Studies and the Seoul Forum for International Affairs released a ROK-Japan joint report, “Envisioning the Next Fifty Years of Japan-Korea Ties (IIPS/SFIA Joint Report).”4 In regards to China, the report notes that it is difficult for the two countries “to fully recognize the nuanced differences of the security interests arising from different geostrategic locations,” and since the ROK is close to China, it “has practical reasons to maintain its cooperative relationship with China, particularly for realizing the unification of the Korean Peninsula.5” The report also pointed out, “Japan should be cognizant of Korea’s geopolitical position as a divided nation that shares borders with China as an immediate neighbor,” while “Japan enjoys relatively safer geopolitical ground” as “an island country detached from the continent.”6


Lastly, the three countries should deepen and widen trilateral dialogue on what has been described as “extended deterrence” of the United States. After the end of the Cold War, this term came to have wider meaning than extended nuclear deterrence or the nuclear umbrella with more emphasis on conventional forces and other available means to avoid and mitigate military or paramilitary conflicts. Fred McGoldrick argues, “what is critical is the ROK’s confidence in the credibility of its overall relationship with the United States and the continued ability of the United States to convince the South Koreans that it has no intention of abandoning them and that the United States will provide credible non-nuclear deterrence guarantees.”7 This perfectly applies to the Japan-US alliance too. Frank and professional discussions on the credibility of US extended deterrence and alliances, as a whole, should be conducted among the three countries at both official and track 2 levels.



The IIPS/SFIA Joint Report quoted above proposed six concrete policies that can be applied to trilateral security cooperation. The following list is a modified version of the report’s proposals on the trilateral context recommending that the three countries should:
1) promote public diplomacy to enhance mutual understanding and to reduce twisted perceptions and misunderstanding;
2) promote track 2 and professional exchanges to share common security interests and strategic perspectives;
3) institutionalize ROK-Japan security ties in addition to already firm ROK-US and Japan-US alliances through grassroots personnel exchanges among military professionals;
4) promote trilateral cooperation towards the unification of the peninsula under ROK’s initiative while forging common understanding on the basic conditions for unification;
5) activate trilateral policy coordination and information sharing on North Korea and China; and
6) promote ROK-Japan, ROK-Japan-US military cooperation in international activities, including UN PKO, global peace operations, humanitarian assistance, and disaster relief operations.8


On the above list, the first points seem to have the foremost importance. This commentary has touched upon track 2 efforts to promote ROK-Japan and ROK-Japan-US security cooperation. The author himself participated in a number of such informal occasions held in the mid- to late 1990s through which personal relations were formed with academics, military officers, and government officials who were still young but becoming more and more influential in Korea and the United States.9 Such personal relations have been extremely useful in the following years including when Japan had difficult relations with the ROK or with the United States as well as in good times. As already twenty years have passed, the three countries should not wait any longer to restart such efforts to build personal bonds in the next generation.


1.Shinobu Miyachi, “日韓共同シミュレ?ション:海の防衛協力” (This is Yomiuri) (February 1999): 274-283.

2.Ralph Cossa, ed., US-Korea-Japan Relations: Building Towards “Virtual Alliance,” (Washington, DC: CSIS, 1999).

3.Lessons learned from the response to the disaster caused by Typhoon Haiyan were shared during the workshop held by Peace Winds America in Tokyo on January 22-23, 2014, http://peacewindsamerica.org/readiness/civil-military-initiative/january-disaster-preparedness-workshop/.

4.The author participated in the preparations for this report, expressed views similar to those in this article, and further articulated policy proposals for the two countries. “Envisioning the Next Fifty Years of Japan-Korea Ties (IIPS/SFIA Joint Report),” Institute for International Policy Studies, June 22, 2015, http://www.iips.org/publications/2015/06/22000000.html.



7.Fred Mcgoldrick, “Nuclear Nonproliferation,” in Scott Snyder, ed., The U.S.-South Korea Alliance (Boulder, CO: Lynne Rienner Publishers, 2012).

8.“IIPS/SFIA Joint Report.”

9.For example, Professor Rhee Sang-Woo of the New Asia Research Institute and Ambassador Okazaki Hisahiko hosted a series of meetings of young security experts from Korea and Japan titled the K-J Shuttle in which a number of promising specialists, government officials, and military officers from the two countries became acquainted and formed bonds of friendship.