Hidemi Saku is the father of Sakura Saku, a young violinist and a friend of the protagonist Shinichi Chiaki. In the story, he is depicted as a businessman whose furniture import company suffered severe financial difficulties due to an economic crisis. To cope with this situation, Hidemi is noted for his personal collection of violins, which includes instruments valued at several million yen, a surprising hobby given that he does not actually know how to play the violin himself. This collection becomes a key factor in the family's storyline, as the sale of his violins ultimately provides the necessary funds to resolve the Saku family's financial problems. His role in the narrative is tied to his relationship with his daughter, and the circumstances surrounding his business and his collected instruments directly affect her life and artistic pursuits.