The Okinawa rail (Gallirallus okinawae) is a species of bird in the rail family, Rallidae. It is endemic to Okinawa Island in Japan where it is known as the Yanbaru kuina (ヤンバルクイナ(山原水鶏), 'Yanbaru rail'). Its existence was only confirmed in 1978 and it was formally described in 1981 although unidentified rails had been recorded on the island since at least 1973 and local stories of a bird known as the agachi kumira may refer to this species. It is a medium-sized and almost flightless rail with short wings and tail, olive-brown upperparts, black underparts with white bars and a red bill and legs. It occurs in subtropical moist forests and in neighbouring habitats. It nests and feeds on the ground but usually roosts in trees. It is classified as an endangered species and is threatened by habitat loss and introduced predators. The species was first described in 1981 by Yoshimaro Yamashina and T. Mano in the Journal of the Yamashina Institute of Ornithology. This was based on a specimen found dead on June 2 at Mt. Fuenchiji in Kunigami District, Okinawa. It was initially placed in the genus Rallus but then moved to Gallirallus, a genus of medium-sized, often flightless, rails found in Australasia and Asia. It is closely related to the barred rail (G. torquatus) and New Britain rail (G. insignis) as well as to the Calayan rail (G. calayanensis), another recently discovered species. It is about 30 cm long with a wingspan of 50 cm and a weight of around 435 g. It is almost flightless and has very short wings and tail. The bill is large and bright red with a whitish tip. The long, strong legs are red as are the iris and eye-ring. The upperparts are olive-brown while the underparts are black with narrow white bars. The face is black with a white spot between the bill and eye and a white line behind the eye, extending back to the side of the neck. The undertail-coverts are dark brown with pale bars. Juvenile birds are paler than the adults and are mottled white below rather than barred. The spot in front of the eye is tinged with brown while the stripe behind is shorter than in the adult. The bill and iris are brownish and the legs and feet are yellow-ochre. It is a noisy bird with a variety of loud calls. It calls most often early and late in the day, usually from the ground but sometimes from trees. Pairs often call together and up to 12 birds have been heard in one area.