Ministry of Defense (Japan)

The Japanese Ministry of Defense is responsible for national defense, overseeing the Ground, Maritime, and Air Self-Defense Forces, formulating defense policy, managing procurement, and coordinating disaster relief. It operates under Japan's pacifist constitution, which limits the use of force to self-defense. The ministry is headed by the Minister of Defense, a member of the Cabinet, and reports to the Prime Minister. Its headquarters is located in Ichigaya, Shinjuku, Tokyo. The ministry also runs educational institutions such as the National Defense Academy and the National Defense Medical College.

As a cabinet-level ministry, it holds both administrative and operational authority over Japan's self-defense capabilities. It maintains a joint staff that integrates planning across the three services. The ministry plays a regulatory role in the defense industry, overseeing export controls and technology transfer. Its responsibilities extend to humanitarian assistance and disaster response, exemplified by deployments after major natural disasters. The ministry also engages in international cooperation through joint exercises and dialogues with allied forces.

The ministry is a government entity, fully funded by the national budget, with no private ownership or parent-subsidiary relationships. It comprises various bureaus, including the Minister's Secretariat, the Defense Policy Bureau, and the Defense Equipment Agency. The 2016 cyber‑attack described in the sources illustrates the ministry's exposure to sophisticated threats, targeting its network via linked academic institutions and prompting temporary internet restrictions while officials assessed the breach. The incident highlighted the need for improved cyber defenses within Japan's defense establishment.