Usuki(臼杵市,Usuki-shi) is a city located on the east coast of Ōita Prefecture, Japan. It is famous for its Usuki Stone Buddhas, a national treasure, and its soy sauce production. Recently it has become known for having the look and feel of a Japanese castle town. It is part of Ōita City's metropolitan area through economics and thus has strong ties to Ōita City.