Satoshi Tsuchida is a second-year Seirin High student and member of the school's basketball team, playing as power forward with jersey number 9. Sporting short, spiky black hair, very thick eyebrows, and distinctive eyes narrowed to thin horizontal lines, he possesses an athletic build at 176 cm tall and 70 kg. Joining the Seirin basketball club shortly after its formation during initial training sessions, Tsuchida primarily serves as a substitute player, supporting from the bench but stepping in when needed. He dedicated significant training over the past year to develop his primary skill: rebounding. During matches like the Interhigh preliminaries against Seihō High, he showcases competence in mid-range shooting alongside his rebounding duties, maintaining a level-headed and positive attitude despite limited playing time. Characterized by shyness and a reluctance to seek attention, Tsuchida holds a genuine passion for basketball. Outside the sport, he enjoys oil painting and building bottle ships, harboring a fondness for cats that often bite him when approached. Academically, he excels in science and English grammar, ranking 81st out of 300 students in the previous year's exams. He serves on the school's broadcasting committee and lives with his parents and one younger sister. Tsuchida is the only known Seirin team member with a girlfriend, her identity separate from the team's social circle. He spends free time on dates and adheres to the motto "Haste makes waste." His favorite food is karaage, and he dislikes singing. He started playing basketball after witnessing Seirin's team introduction during a school assembly. He appears with the Seirin team during the Winter Cup, including the opening ceremony and bench support during matches, and participates in the events of "Last Game" as a roster member, with no documented unique narrative contributions specific to spin-offs, OVAs, or "Last Game" beyond this established role.