The Kawasaki OH-1 (nicknamed Ninja) is Japan's first indigenous observation/combat helicopter intended to replace the older, local-built US OH-6. Although designated as an observation helicopter, the OH-1's design more closely resembles that of a conventional gunship on account of its narrow fuselage, stepped tandem cockpit, crew protection armor, and prominent stub wings which can carry a variety of stores, primarily air-to-air missiles for self-defense. It's other notable structural feature is a Fenestron ducted fan anti-torque tail while avionics include a targeting system involving FLIR, TV, and laser ranging systems. Although the total size of the project has been scaled down due to budget cuts, the OH-1 is slowly being introduced to the Japanese Ground Self-Defense Force with the possiblity of a dedicated attack variant being developed to replace the AH-1 Cobra.

First flight of the XOH-1 prototype (known originally as the OH-X) took place on 6 August 1996 with production units entering service with the JGSDF in the year 2000 as the OH-1. An requirement for a future attack helicopter known as the AH-X (or tentatively AH-2) could be based on a proposed version known as the OH-1Kai. This model would feature amour-plated forward and central fuselage, upgrated engines and transmission, and additional weapons (particularly air-to-ground) capability.