Osamu Kajisa (加治佐修, Kajisa Osamu), born on December 30, 1973, is a Japanese mangaka and former assistant to Masashi Kishimoto. Following his work on Naruto, he went on to moderate success and is best known for the manga series Tattoo Hearts, which was serialised in Weekly Shōnen Jump in 2003.
- Happening Go Go!! (1999, Akamaru Jump Summer)
- Nagumo (2000, Akamaru Jump Winter)
- Tattoo Hearts pilot (2000, Weekly Shōnen Jump)
- Tattoo Hearts (2003, Weekly Shōnen Jump)
- Now and Zen! (2003, Weekly Shōnen Jump)
- Nora, Sora (2005, Akamaru Jump Spring)