By Dr. Ju Hyung Kim.
As the threat of simultaneous crises in East Asia looms larger—whether in the Taiwan Strait, the Korean Peninsula, or both—the likelihood that U.S. special operations forces (SOF) will be called upon to operate across national boundaries in compressed timelines is no longer hypothetical. In the event of a full-scale war on the Korean Peninsula, U.S. Forces Japan (USFJ) will not just support conventional operations—they will serve as the SOF launch pad, logistics hub, and potential battlespace.
U.S. SOF presence in Japan, including elements of the 1st Special Forces Group (Airborne) and associated support units, plays a critical role in enabling forward operations for the Combined Forces Command in Korea. These units, though sometimes overshadowed by conventional reinforcements, are uniquely positioned to handle the “gray zone” and time-sensitive missions that define the early hours of a North Korean contingency.
Why SOF Will Launch from Japan
Under existing U.S.-ROK warfighting concepts—centered on OPLAN 5015, U.S.-ROK combined forces aim to degrade North Korea’s ability to wage war within the first 72 hours. This includes targeting its long-range artillery, ballistic missile units, and command-and-control nodes—most of which are hidden, hardened, or mobile. Achieving these objectives requires deep-strike capabilities, real-time intelligence, and direct action missions—core SOF competencies.
While U.S. Air Force bombers from Guam and the mainland would eventually contribute, SOF units deployed from Japan would likely serve as the tip of the spear in locating and destroying these time-critical targets. Forward operating locations such as Kadena Air Base, Yokota, and Camp Zama are ideal for such missions, offering quick access to the Korean theater and established logistics chains.
A Two-Front Fight: Infiltration and Interdiction
What makes the role of SOF even more vital is the asymmetric dimension of North Korea’s war strategy. Pyongyang maintains one of the largest special operations forces in the world – numbering upwards of 200,000. In the opening days of a conflict, North Korea may attempt to send SOF units not only into South Korea but into Japan, targeting U.S. and Japanese bases, logistics hubs, and civilian infrastructure.
This is not theoretical. In 2002, the U.S. and Japan jointly developed CONPLAN 5055, which envisioned several hundred North Korean guerrillas infiltrating Japanese metropolitan areas during a Korean contingency. A later upgrade, OPLAN 5055, further detailed Japan’s response, including protection of 135 critical sites and integration of police, JSDF, and U.S. military units for rear-area defense.
For U.S. and allied SOF, this means a two-front mission: launching deep-penetration raids into North Korea from Japan, while simultaneously countering sabotage and infiltration on Japanese soil. This duality requires enhanced interoperability with Japanese SOF units – especially the Ground Self-Defense Force’s Special Forces Group – as well as local police and intelligence services.
Despite strong U.S.-Japan bilateral defense ties, SOF interoperability remains limited, particularly in trilateral scenarios involving South Korea. Language barriers, legal restrictions on Japanese overseas operations, and differing rules of engagement complicate coordination. Yet recent updates to the 2015 U.S.-Japan Defense Guidelines and the establishment of the Alliance Coordination Mechanism (ACM) now permit more seamless integration—even in gray-zone or hybrid warfare environments.
If U.S. special operations forces are to operate effectively from Japanese bases into the Korean theater—and simultaneously respond to threats on Japanese soil—the depth and frequency of joint training must increase. This should include urban counter-infiltration exercises that simulate North Korean SOF attacks on U.S. bases and critical infrastructure within Japan, enhancing preparedness for hybrid warfare scenarios. Equally important are joint high-value target (HVT) tracking and elimination drills, conducted in coordination with Japan’s Self-Defense Forces and South Korean special units, to improve trilateral operational synergy. Hostage rescue operations involving U.S. citizens, diplomats, or allied personnel in contested environments should also be rehearsed under realistic conditions. Finally, joint maritime SOF insertion training should be prioritized—particularly in the coastal areas of Okinawa and Kyushu, where the threat of infiltration by sea is highest and rapid littoral response would be essential.
History Repeats: USFJ as the Strategic Anchor
During the 1970s, when U.S. ground presence in Korea was sharply reduced and the Vietnam War had strained American public will, USFJ became the critical backstop to prevent a Korean security vacuum. It is now known that Kim Il-sung explored options for invasion during that period, likely assessing whether the U.S. would respond forcefully. The presence of U.S. SOF and rapid-deployment forces in Japan contributed to the deterrence calculus.
Today, as the Indo-Pacific security environment grows more volatile, this historical lesson is being revisited. USFJ not only enables strategic depth but may also buy time—by launching SOF missions quickly and credibly before political decisions on full-scale U.S. reinforcements are finalized.
Analysts and public doctrine underscore that the first 72 to 96 hours of a Korean contingency are decisive. Allied war‑gaming and planning cycles under OPLAN 5015 emphasize a door‑kick window during which initial strikes against North Korean artillery, missile batteries, and leadership nodes are critical to prevent operational collapse. If Seoul falls or U.S. reinforcements are delayed due to disrupted logistics, the cost of retaking lost ground—politically and militarily—becomes exponentially higher. In such a compressed timeline, U.S. SOF units based in Japan are among the few forces capable of executing high-value strikes early enough to alter the trajectory of the war.
Moreover, the defense of Japanese soil against infiltration and sabotage will fall not only to conventional Japanese forces but likely to joint SOF teams trained in rapid urban clearance, infrastructure protection, and inter-agency coordination.
Deterrence Through Preparedness
For decades, policymakers and military planners have focused on North Korea’s threat to South Korea. But as Pyongyang refines its asymmetric warfare capabilities, the threat to Japan—and the role of SOF in countering it—must now take center stage.
U.S., Japanese, and South Korean special operations communities must plan not only for offensive missions from Japan into Korea, but also for defensive operations in Japan itself. Whether flying out of Kadena, staging from Yokota, or operating alongside JSDF in Tokyo, U.S. SOF will be indispensable—not just in winning the next Korean war, but in ensuring it never starts.
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Dr. Ju Hyung Kim is President of the Security Management Institute; a defense think tank affiliated with the South Korean National Assembly. He is currently adapting his doctoral dissertation – titled Japan’s Security Contribution to South Korea, 1950 to 2023 – into a forthcoming book.