Tomahawk cruise missiles have pinpoint accuracy with a range of more than 1,000 kilometers. They can be launched from the ground as well as vessels and submarines, flying at subsonic speeds and low altitudes to avoid detection by radar.
First used by the US military in the 1991 Gulf War, Tomahawks were also deployed in the 2003 Iraq War and the Syrian military attack five years ago. They are currently part of the US and British militaries' arsenal, among others.
Australia announced last year that it will equip some of its warships with Tomahawk missiles.
Japan's security strategy and Tomahawk cruise missiles
Japan's possible purchase of the weaponry comes as its government works on the revision of its security platform, including the national security strategy.
The government wants to ensure that Japan possesses counterstrike capabilities to shore up its self-defense, including the ability to strike enemy missile launch bases.
Japan's Ground Self-Defense Force's improved Type 12 surface-to-ship missile system is the center of its counterstrike initiative, but it will not be operational until fiscal 2026 or later. In the meantime, Tomahawks are being considered.
Japan's security strategy and the regional situation
The Tomahawk is regarded as highly reliable. If the weaponry is purchased, Japan's Maritime Self-Defense Force will need to refurbish equipment that launches SM-3 interceptor missiles from its Aegis destroyers.
It is understood the Japanese government has been sounding out Washington, which was concerned about reactions from China and South Korea.
But as China expands its military presence, US officials have reportedly shown understanding about Japan's desire to acquire Tomahawks.
The longstanding postwar security policy that defines the Japan-US alliance is known as the "Spear and Shield". The US is the spear, and Japan the shield -- but these roles may be shifting as the security environment prompts policy revisions.