Sumire Hirose is a third-year student at Shiraitodai High School in West Tokyo and a supporting character in the manga "Saki". She is a close friend of teammate Teru Miyanaga and the only person known to Teru who seems to have had prior knowledge of Saki's existence. Sumire is calm and polite to her friends and opponents. She never rushes to make her decision and always calmly thinks about it throughly.