A Historical Turning Point in Japan's Defense Policy: The Establishment of the Expert Committee for the Revision of the Three Security Documents and the Reality of the "Southern Shield"

On April 27, 2026, Prime Minister Sanae Takaichi held the first meeting of the "Expert Meeting on Comprehensive National Power and Security" at the official residence. This signifies the commencement of serious discussions aimed at revising three security-related documents: the National Security Strategy, the Defense Program Guidelines, and the Mid-Term Defense Force Build-Up Plan, by the end of the year. During the meeting, Prime Minister Takaichi stated, "In order to protect our country's peace and independence, we must continue to proactively advance the fundamental strengthening of our defense capabilities," clearly indicating a stance to thoroughly enhance Japan's comprehensive national power by organically linking diplomatic power and defense power with economic power, technological power, information power, and human resources. The meeting is expected to compile recommendations by autumn, and the government plans to revise the three documents by the end of 2026.

The backdrop of this movement is the significant increase in military pressure from China, North Korea, and Russia. Particularly, China has been positioned as Japan's greatest national security threat since 2019, and the risk of spillover to the southwestern islands in the event of a Taiwan emergency is central to the defense plan. Additionally, Russia's invasion of Ukraine and the dramatic changes in the Middle East—concerns over the blockade of the Strait of Hormuz due to U.S.-Israel military actions regarding Iran—are also weighing heavily on Japan from the perspective of energy security. Domestically, voices prioritizing the stable supply of naphtha have erupted on social media, highlighting the inseparability of security and economic security once again.

In response to this dramatic change in the security environment, Japan is hastening the establishment of a new defense posture referred to as the "Southern Shield." In late March 2026, the Japan Ground Self-Defense Force deployed the latest 25-type anti-ship guided missile at the Kengun Garrison in Kumamoto Prefecture. This missile has achieved a significant extension of range from approximately 200 kilometers with the conventional 12-type anti-ship guided missile to about 1,000 kilometers, capable of covering extensive maritime areas from southern Kyushu to parts of mainland China. Its low observability design, considering stealth, and the in-flight re-targeting capability (UTDC) via satellite communication are extremely important, providing dynamic engagement capabilities against moving maritime targets.

The development of the 25-type SSM is not merely an update of a single piece of equipment. The Ministry of Defense is developing ship-launched and aircraft-launched variants for deployment by fiscal year 2028, and plans to operationally deploy hypersonic guided missiles and high-speed glide vehicles (HVGV) by 2032. This indicates that Japan is effectively expanding the traditional framework of "defensive defense" under the name of "counterstrike capability." As the Defense Minister described in a press conference, "the most serious and complex security environment since the post-war period," Japan's defense posture is fundamentally being restructured with a focus on the southwestern region. The deployment of electronic warfare units and air assets to the southwestern islands is also progressing, and the allocation of resources for the defense of the first island chain is increasing year by year.

This strategic transformation in Japan is not limited to domestic policy shifts but is also having a profound impact on the nature of regional alliances and partnerships. In the joint U.S.-Philippines exercise "Balikatan 2026," which began on April 20, 2026, Japan participated for the first time as an official participant, with Canada also newly joining. Approximately 17,000 military personnel from seven countries— the United States, the Philippines, Japan, Australia, New Zealand, France, and Canada—are participating in the exercise. The U.S. Marine Corps' 3rd Marine Littoral Regiment, based in Hawaii, has deployed the Naval Expeditionary Missile System (NMESIS) equipped with Naval Strike Missiles to Cagayan International Airport in northern Luzon. This unmanned launcher, with a range of 185 kilometers, is positioned to cover the Luzon Strait, which separates Taiwan and the Philippines, embodying the maritime denial capabilities in the first island chain.

The Japan Ground Self-Defense Force is also planning to bring the 88-type anti-ship guided missile to Balikatan and participate in anti-ship firing training alongside the BrahMos missile of the Philippine Marine Corps. On April 24, the Japan Maritime Self-Defense Force's escort ships conducted a group sailing exercise with vessels from the Philippines, Australia, Canada, the United States, and the U.S. Coast Guard. The attendance of the Chief of Staff of the Self-Defense Forces and the Commander of the Maritime Self-Defense Force's Combined Operations Unit at the opening ceremony in Manila symbolizes Japan's efforts to build a multilateral security network in the region as a secondary connector beyond the hub-and-spoke structure of its ally, the United States.

In this context, it is noteworthy that Japan has historically relaxed its arms export regulations. On April 21, 2026, the Japanese government officially lifted the ban on the export of lethal weapons. This is an extremely significant policy shift, the first of its kind since the post-war period, expanding the transfer of defense equipment, which had previously been limited to five non-combat areas—rescue, transportation, surveillance, and surveying—to all defense equipment in principle. While the export destinations are limited to 17 countries with which confidentiality agreements have been concluded, the Chief Cabinet Secretary stated, "We have actually received requests to reactivate retired escort ships." This is linked to the agreement for the export of six Abukuma-class escort ships being pursued with the Philippines. Additionally, contracts for the construction of new frigates for Australia have also been concluded, marking Japan's emergence as a defense equipment exporting country in both name and reality.

However, these changes require careful discussion domestically. The acquisition of counterstrike capabilities significantly expands the legal definition of self-defense, raising questions from opposition parties and academia regarding its consistency with Article 9 of the Constitution. There are also concerns regarding the lifting of the arms export ban, with criticisms about the lack of transparency in the operational standards for preventing outflows to conflict areas and special circumstances. With the deterioration of the situation in the Middle East, discussions regarding the prioritization of securing stable energy resources, including naphtha, and strengthening defense capabilities are becoming more active, necessitating a view of security policy as a comprehensive policy issue directly linked to the lives of citizens, rather than merely a military issue.

As discussions on revising the three security documents intensify under the Takaichi administration, Japan's defense policy stands at the most critical crossroads since the promulgation of the Constitution in 1947. The deployment of the 25-type SSM, the development of hypersonic weapons, formal participation in the Balikatan exercise, and the lifting of arms export regulations—these are not isolated policies but form a single strategic trend. As Japan builds the Southern Shield while deepening cooperation with allies and establishing its own defense industrial base, it holds the potential to bring irreversible changes to the security environment in Northeast Asia. The success or failure of this endeavor hinges on whether it can simultaneously clear the two challenges of domestic consensus-building and strengthening regional partnerships.