The Tōmaru (唐丸) is a Japanese breed of long-crowing chicken.

It is one of four Japanese long-crowing breeds, the others being the Koeyoshi, the Kurokashiwa and the Tōtenkō.

[7] The Tomaru was registered as a Japanese natural monument of Niigata Prefecture in 1939.

[8]: 101 The Tōmaru has only one colour, black with a greenish sheen.

The tail is held low, but higher than horizontally; although the sickle feathers may be long enough to touch the ground, this is not usually considered a long-tailed breed.