Birth name: Atsushi Shirakawa (白川 篤史)

Tenmon (天門), born Atsushi Shirakawa, is a Japanese music composer from Tokyo, Japan born in 1971. He worked in the Nihon Falcom Corporation as one of the members of Falcom Sound Team J.D.K.. During his time with Falcom, he has composed much music for Falcom games, most notably Brandish.

Having known Makoto Shinkai as a co-worker in Minori he has composed music for Shinkai's works since Kanojo to Kanojo no Neko. He is perhaps best known for creating the soundtracks for Shinkai's subsequent works, Hoshi no Koe, Kumo no Mukou, Yakusoku no Basho, Byousoku 5 Centimeter, and most recently, Hoshi wo Ou Kodomo.