The First Deployment of Combat Troops and the Shift to Arms Exports After the War: The Major Transformation of Japan's Security Indicated by Balikatan 2026

On May 8, 2026, the U.S.-Philippines joint military exercise "Balikatan 2026," which was conducted across the Philippines, concluded. This exercise, which took place over approximately three weeks starting from April 20, involved around 17,000 troops, making it the largest scale to date. It is positioned as a historic turning point in post-war Japan's security policy, particularly regarding the depth of Japan's involvement.

Japan dispatched approximately 1,400 Self-Defense Force personnel to the Philippines for this exercise. This marks the first instance since World War II that Japan has sent combat troops to Philippine territory. The deployment is the first full-scale operation under the Japan-Philippines Reciprocal Access Agreement (RAA), which came into effect last year, and included the Japan Maritime Self-Defense Force's helicopter carrier "Ise," the transport ship "Shimikita," the destroyer "Ikazuchi," and C-130H transport aircraft, as well as the Japan Ground Self-Defense Force's Type 88 anti-ship missile (SSM-1). On May 6, anti-ship firing training targeting decommissioned Philippine Navy vessels was conducted in the South China Sea off the coast of Laoag City in northern Luzon, where Defense Minister Shinjiro Koizumi observed the Self-Defense Forces firing live ammunition. Reuters reported that "Japan has taken on a combat role in the South China Sea for the first time since World War II," analyzing that this exercise symbolizes a "historic shift" in Tokyo's defense posture.

Notably, this exercise marked the first participation of the Japan Maritime Self-Defense Force's US-2 amphibious rescue aircraft in Balikatan. Manufactured by ShinMaywa Industries, this high-performance amphibious aircraft conducted patient evacuation training at sea in coordination with the U.S. Navy's dock landing ship "Ashland" (LSD-48) off the coast of Oyster Bay, Palawan, on April 27. The US-2 has world-class capabilities, able to take off and land in open waters with wave heights of up to 3 meters, and is regarded as a significant asset that dramatically enhances interoperability for rescue and humanitarian assistance capabilities in the South China Sea. Photos released by the U.S. Indo-Pacific Command on May 2 vividly captured the US-2 landing on the South China Sea and transferring crew members to the "Ashland."

Meanwhile, vessels of the People's Liberation Army Navy of China continued to monitor from a distance, clearly indicating the rising tensions in the South China Sea. The Chinese Navy currently boasts over 400 vessels and continues to expand rapidly, including aircraft carriers, destroyers, and submarines, raising concerns about a deterrence gap in the first island chain, which is accelerating the strengthening of cooperation among the U.S., Japan, and the Philippines. At an event held by the Hudson Institute on May 6, a former government official warned that "the free, open, and stable international order is under tension, and Japan is facing the most severe and complex security environment since World War II."

In parallel with the military exercises, there were historic developments in terms of equipment transfers. On May 5, Defense Minister Koizumi and Philippine Defense Secretary Teodoro agreed to establish a bilateral working group to materialize the transfer of Japan Maritime Self-Defense Force destroyers and aircraft to the Philippines during their meeting in Manila. The focus is on the "Abukuma" class destroyers (DE) of the Japan Maritime Self-Defense Force, and if realized, it would be the first export of lethal equipment from Japan under the revised Three Principles on Transfer of Defense Equipment, which were amended on April 21, 2026. The Diplomat magazine described this move as "representing a broad transformation of security adaptation for middle powers in the Indo-Pacific, beyond mere equipment transfer."

The "Abukuma" class, which is considered for transfer, has a standard displacement of 2,000 tons, a length of 109 meters, and is a balanced destroyer for anti-submarine and surface warfare, making it a suitable platform for the geographical characteristics of the Philippines, which consists of many islands. Given that the Philippine Navy currently possesses only a limited number of frigates and corvettes, even a second-hand vessel would directly contribute to enhancing the quality of its military capabilities. The Philippines' "Re-Horizon 3" modernization plan anticipates a budget of approximately 2 trillion pesos by 2033, but a short-term capability gap is unavoidable, and second-hand platforms are positioned not merely as stopgaps but as strategic means.

This decision symbolizes a fundamental shift in Japan's security policy. The 2026 revision of the Three Principles on Transfer of Defense Equipment explicitly permits the export of lethal equipment under certain conditions, and the transfer of the "Abukuma" class will serve as a litmus test. Tokyo is beginning to position defense equipment transfers not merely as industrial policy or economic issues but as strategic means for enhancing interoperability with allied nations and shaping the regional balance of power. At the same time, Japan's government’s OSA (Official Security Assistance) program continues to expand, with support targets expected to grow from four countries and approximately 2 billion yen in fiscal year 2023 to 12 countries by fiscal year 2026, with the budget scale projected to double.

Additionally, on May 4, Defense Minister Koizumi met with Indonesian Defense Minister Prabowo in Jakarta and signed a Japan-Indonesia Defense Cooperation Agreement. This agreement targets cooperation in areas such as humanitarian assistance-disaster relief, joint training, and maritime security, indicating that the construction of defense partnerships in Southeast Asia is accelerating following last month's easing of arms export restrictions.

The security environment in Northeast Asia is also showing increasing tension. On May 8, North Korean state media reported that Chairman Kim Jong-un inspected a major munitions factory on May 6 and ordered the deployment of a new long-range artillery system within the year. This new artillery is said to have the capability to target the metropolitan area of South Korea, and it was also revealed that North Korea's first full-fledged naval destroyer, "Choi Hyun," is expected to be commissioned about three weeks later. On May 7, Kim Jong-un personally confirmed the maneuverability of the ship in the Yellow Sea and demonstrated a strong commitment to naval power development by having lunch with sailors aboard the vessel alongside his daughter. In April, North Korea conducted at least its seventh ballistic missile launch, with multiple launches, including the possibility of SLBMs, confirmed from off the coast of Sinpo, clearly indicating a pattern of gradually escalating strategic provocations amid ongoing crises in the Middle East, such as the situation in Iran.

The Balikatan 2026 exercise and the series of diplomatic developments associated with it indicate that the security structure in the Indo-Pacific is undergoing a qualitative transformation. While Japan nominally maintains the framework of "defensive defense," its substance has significantly shifted towards "proactive defense," expanding the perimeter of territorial defense through forward deployment and equipment transfers with allied nations. The waters from the Bashi Channel in the Philippines to the South China Sea and the East China Sea are lifelines for Japan's energy security, and the strategic significance of the Self-Defense Forces standing in a combat posture for the first time since World War II at the forefront of this sea lane defense is immeasurable. Moving forward, the institutionalization of maritime security cooperation centered around Japan, the U.S., the Philippines, and Australia, along with the responses from China and North Korea, will become the most critical variables defining the security order in Northeast Asia.