Hajime Tsuji is a supporting character in the anime Three Leaves, Three Colors. He is a male high school student recognizable by his blue hair, which is cut to ear length, and his blue eyes. His birthday is May 17, making his zodiac sign Taurus, and his blood type is O.

Hajime is part of a comedic duo with his twin sister, Sasame Tsuji. The pair are known for their entertaining dynamic, which adds to the show's humor. Hajime's primary personality trait is his competitive drive, specifically directed at one of the main characters, Futaba Odagiri. He considers Futaba to be his rival.

His main motivation revolves around this rivalry with Futaba. Hajime is determined to defeat her in eating challenges, yet he consistently fails to do so, which leaves him perpetually miffed. This recurring failure is a running joke associated with his character. His sister, Sasame, is supportive of his goals and wants to see him happy. However, her desire to help her brother leads her to take a dislike to Futaba, whom she perceives as being unnecessarily cruel to Hajime by consistently beating him.

In addition to his connection with his sister and his rivalry with Futaba, Hajime is also indirectly involved in other character dynamics through Sasame, who develops a significant admiration for another main character, Youko Nishikawa.

Information regarding Hajime Tsuji's background prior to the events of the story, a detailed arc of personal development, and any specific notable abilities beyond his participation in eating contests is not available.