Kūsō Kagaku Ninkyōden: Gokudō Ninja Dosuryū (空想科学任侠伝 極道忍者ドス竜, Kūsō kagaku ninkyō den gokudō ninja dosu ryū), better known for its international title as The Ninja Dragon (not to be confused with the 1986 Hong Kong film Ninja Dragon (1986) directed by Godfrey Ho), is a 1990 Japanese direct-to-video action film released by the Tohokushinsha Film Corporation. It was directed by Go Nagai, his third film as director and his first as a solo director. The film was produced by Dynamic Planning, Moby Dick and the Tohokushinsha Film Corporation. A Laserdisc version was also released in Japan.