OVA
Description
Shuichiro Ōishi, vice-captain of Seishun Academy's tennis team, is a 15-year-old born April 30. A Taurus with blood type O, he stands 175 cm tall, weighs 55 kg, and plays right-handed. Specializing exclusively in doubles as a counter-puncher, he partners with Eiji Kikumaru in the "Golden Pair." His signature "Moon Volley" technique employs a Wimbledon Tour Merit racquet and Nike Ready Air Zoom Sterling shoes.

Concern for others defines Ōishi's persona, earning him the "Mother of Seigaku" moniker. He prioritizes collective welfare, exemplified when he injured his wrist aiding a pregnant woman en route to a tournament, missing a critical match. He remained at the hospital until her husband arrived despite his team's reliance on him. Typically composed, he displays intensity when advocating for yakiniku or reacting to excessive teasing. His leadership emphasizes reliability and emotional support.

Ōishi attended Seishun Second Elementary before Seishun Academy. His family comprises a father (tax officer), mother, and younger sister. His uncle Akitaka treated teammate Kunimitsu Tezuka's shoulder injury. Academically, he struggles in mathematics but excels in English. Interests include astronomy, fishkeeping, swimming, and romance media. He prefers girls who wear glasses and aims to become a doctor. Additional traits encompass fear of thunder, pollen allergies, and the ability to determine young birds' gender.

In the National Tournament arc, Ōishi competed in Seigaku's championship quest, focusing on strategic doubles coordination and sustaining team morale under pressure. Post-junior high, he joined Japan's U-17 World Cup team as No. 16 (formerly) and later No. 11 in the Middle School Division, assigned to Court 2 during training.

Ōishi evolved from an anxious, eccentric freshman to a composed leader. His dedication remains solely to doubles tennis, with no official singles matches. Post-nationals, his skills progressed through international competitions.