The Evolution of Japan’s Ballistic Missile Defense Strategy

Japan is reassessing its approach to ballistic missile defense amidst evolving threats from North Korea. As North Korea continues to advance its ballistic missile development, the frequency and types of launches vary, requiring Japan to consider the development of hypersonic glide vehicles and cruise missiles. Additionally, North Korea’s pursuit of nuclear weapons adds to the complexity of the threat.

Initially, the Japanese government planned to deploy the Aegis Ashore missile defense system to protect the entire country from North Korean ballistic missiles. However, the procurement was cancelled, and Japan shifted its focus to the Aegis destroyer fleet. These ships have been upgraded since 2007 to have ballistic missile defense capabilities, and Japan currently has eight ballistic missile-capable ships in its fleet.

The decision to purchase and develop longer-range missiles for counter-strike contingencies has caused Japan to rethink its traditional approach to ballistic missile defense. The Japanese government now aims to exercise deterrence denial and punitive deterrence against the North Korean ballistic missile threat.

The evolution of North Korea’s missile capabilities, particularly the development of mobile ballistic missiles launched from various locations, has made tracking and defending against these missiles increasingly difficult. The Aegis Ashore units were initially intended to address this challenge, but after difficulties in deployment coordination, the project was suspended.

As an alternative, the Japanese government plans to build two Aegis-equipped vessels to replace Aegis Ashore. However, this solution alone cannot achieve the goal of protecting all of Japan from ballistic missiles around the clock. Therefore, the operational requirement for Aegis-equipped destroyers as a replacement for Aegis Ashore is yet to be determined.

In late 2022, the Japanese government prepared three security-related documents, including the National Security Strategy, the National Defense Strategy, and the Defense Buildup Plan. These documents reflect a significant shift in Japan’s security policy, including an increase in the defense budget and the retention of a counterstrike capability.

Japan’s ballistic missile defense strategy is continuously evolving to adapt to the changing threat landscape. As North Korea’s capabilities advance, Japan will continue to reassess and enhance its defense measures to ensure the safety of its territory and citizens.

Sources:
– Japan Times: https://www.japantimes.co.jp/opinion/2023/05/31/commentary/japan-commentary/evolution-japans-ballistic-missile-defense-strategy/
– Ministry of Defense, Japan: https://www.mod.go.jp/e/publ/w_paper/wp2020/pdf/02_Part1_Chapter1_Section2.pdf