A Historical Shift in Japan's Security Policy: The Transition from "Defensive Defense" to "Proactive Deterrence" Accelerated Under the Takai Administration

In late April 2026, the first meeting of the "Expert Meeting on Security from the Perspective of Comprehensive National Power" was held at the Prime Minister's Official Residence in Nagatacho, Tokyo, clearly indicating that Japan's security policy is at a historic crossroads. Prime Minister Sanae Takaichi declared at the outset of the meeting, "The international order that has been relatively stable since the Cold War has become a relic of the past," and stated her commitment to actively pursue a fundamental strengthening of defense capabilities. The establishment of this expert meeting aimed at revising the three security documents signifies Japan's clear shift from the post-war principle of "defensive defense" to "proactive deterrence."

The three security documents currently being revised—namely, the National Security Strategy (NSS), the National Defense Strategy (NDS), and the Defense Build-Up Program (DBP)—constitute the "blueprint, strategy, and budget" of Japan's security policy. In the previous revision in 2022, Japan declared its possession of "counterstrike capabilities," and this revision aims to advance that to a new level, completing the transition from declaration to operational use. The members of the expert meeting include Kenichiro Sasae, former ambassador to the U.S., Tetsuro Kuroe, former Deputy Minister of Defense, Professor Kazuhito Suzuki from the University of Tokyo's Graduate School of Public Policy, and Professor Noriko Endo from Waseda University, among 15 others, and broad discussions across party lines are expected.

The movement symbolizing the transformation of Japan's security policy is not limited to this expert meeting. On April 21, the "Three Principles on Transfer of Defense Equipment," which had restricted the export of lethal weapons, was abolished. The previous export framework, which was limited to five areas—rescue, transport, surveillance, and mine clearance—has been removed, effectively allowing the overseas transfer of lethal weapons. This aims to enhance the competitiveness of Japan's defense industry and improve combat readiness in times of crisis, but it also signifies the collapse of the principle of "prohibition on arms exports" that Japan has maintained since the post-war period. Prime Minister Takaichi reiterated her strong resolve to strengthen defense capabilities, stating at the meeting, "There is no time to lose."

Another noteworthy change is the alteration of the Self-Defense Forces' rank titles. For the first time since the establishment of the Self-Defense Forces in 1954, the government plans to change the rank names from the current "1st Class," "2nd Class," and "3rd Class" to "Colonel," "Lieutenant Colonel," and "Major," which were used in the former Imperial Japanese Army. The chiefs of staff of the Ground, Maritime, and Air Self-Defense Forces will be referred to as "Generals," and flag officers will be called "Lieutenant Generals." The government cites "international standardization" as the reason, but neighboring countries, including China and South Korea, are strongly wary of this as a sign of a revival of militarism. Chinese Foreign Ministry spokesperson Mao Ning warned last November that Japan's right-wing forces are attempting to escape the constraints of the pacifist constitution. Within Japan, critical voices have emerged on social media, stating that "the Takaichi Cabinet is focusing too much on returning to the pre-war era and militarism."

In the 2026 budget, 6 billion yen has been allocated for AI research related to defense, and Fujitsu has launched the "Defense Tech Accelerator" under the leadership of the Acquisition, Technology & Logistics Agency (ATLA). This program adopts an "open innovation" approach that integrates startups, academic institutions, and traditional companies, aiming to permeate AI throughout the defense system. It is poised to introduce intelligent systems in areas requiring operational analysis, mission planning, and rapid decision-making. Additionally, on March 31, 2026, the deployment of the Type 25 Surface-to-Ship Missile (SSM) with a range of 1,000 kilometers and the Type 25 High-Speed Glide Projectile (HVGP) with a range of several hundred kilometers began. The rapid military utilization of low-cost drones and AI, demonstrated in the Ukraine war and the Iran-U.S. conflict in the Middle East, is compelling Japan's defense planners to respond to "new forms of warfare."

Significant changes are also underway in the context of the Japan-U.S. alliance. The U.S. Navy has included an $1.85 billion feasibility study in its 2027 budget to begin exploring the adoption and joint production of Japan's Mogami-class frigates and South Korea's Daegu-class frigates. The Mogami-class features a 5,500-ton stealth hull and advanced automation, while the Daegu-class is 3,600 tons and equipped with a quiet propulsion system. Both ships are equipped with U.S. standard systems such as the MK-41 Vertical Launch System. While China is building 6 to 10 destroyers annually, the U.S. has remained at a pace of only one-quarter to one-sixth of that, making the utilization of allied shipbuilding capabilities an inevitable choice. This could mark the first instance since World War II that the U.S. procures major surface combatants from foreign partners.

A groundbreaking defense industrial cooperation agreement, including the provision of 11 frigates, was officially concluded between Japan and Australia in April 2026. This initiative, which integrates Japan's sensor technology, U.S. missile systems, and Australia's shipbuilding capabilities, is expected to define a new strategic reality in the Indo-Pacific region. The participation of Japan's Maritime Self-Defense Force escort ships in the Balikatan exercises and the expansion of activities around the Philippines also indicate that Japan's defense reach is extending from the southwestern islands to the South China Sea.

In terms of Japan-South Korea relations, a visit by the defense minister to South Korea is planned, and a deputy-level "2+2" meeting of foreign and defense ministers is scheduled for early May. Practical cooperation has already begun, as evidenced by the Japan Air Self-Defense Force providing aerial refueling support to South Korean aircraft in January 2026. However, there remains a strong public sentiment in South Korea, rooted in historical context, that is cautious about military cooperation with Japan, leading to a tug-of-war between security necessities and domestic political constraints.

The rapid transformation of Japan's security policy is a response to the complex changes in the security environment, including China's military expansion, North Korea's nuclear and missile development, the protraction of Russia's invasion of Ukraine, and the U.S.-Iran conflict in the Middle East. However, the speed and scale of these changes fundamentally challenge the identity of Japan as a "peaceful nation" that has been built since the post-war period. The transition from "defensive defense" to "proactive deterrence" is being advanced under the banner of a fundamental strengthening of defense capabilities, but what lies beyond that? How will Japan's political leadership and its citizens find a balance between the realistic necessities of security and historical lessons? This will likely become the most significant variable affecting the stability of Northeast Asia in the future.