Nihon Seikaiha
- Country: Japan
- Type: Commercial
- Website: www.seikaisha.co.jp
- Update: 05-02
Ltd. (せいかいしゃ, STAR SEAS COMPANY) is a Japanese publishing house founded in 2010, headquartered in Tokyo, and a wholly owned subsidiary of Kodansha. In 2010, it launched "Frontline", a website that provides free access to novels, manga, and other works.
