The resulting OH-1, nicknamed Ninja, is a conventional machine that is relatively small and of typical gunship helicopter configuration. Its structure comprises, by weight, 40 per cent carbonfibre-reinforced plastics, and it features a fenestron type tail rotor.

Each crew member has two LCD colour multi-function displays, and the gunner has a head-up display. The mission avionics include a trainable roof-mounted Kawasaki package (forward of the main rotor) with a Fujitsu thermal imager, NEC colour TV camera and NEC laser rangefinder. Protection is enhanced by the installation of an infra-red jammer on the helicopter's spine to rear of the main gearbox.

The first of six prototypes made its initial flight on 6 August 1996, and the first of a possible 150 to 200 OH-1s was delivered to the JGSDF on 24 January 2000. A total of 14 OH-1s has been ordered for delivery by 2001. The JDA may revise the OH-1 to meet its AH-X light attack helicopter requirement. This would probably feature MTR-390 or T800 engines, allowing the introduction of a heavier weapons load and revised mission avionics. The projected designation of the AH-X production model is AH-2.