TV-Series
Description
Jin Akutsu, a third-year at Yamabuki Middle School, possessed extraordinary natural athleticism, channeled primarily into tennis. He played without formal training, relying instead on innate reflexes, remarkable flexibility, and "animalistic speed" to hit balls from seemingly impossible positions and generate high shot velocities. Standing 183 cm tall and weighing 71 kg, he played right-handed. His appearance transformed markedly from a brown bob in his pre-teens to bleached spiky white hair as an older teen.

Akutsu displayed a violent and rebellious nature, frequently skipping class, smoking, and initiating fights. He harbored a deep aversion to authority, lashing out aggressively at any perceived command with his signature phrase, "Don't order me." Exceptions existed only for his childhood friend Takashi Kawamura—known from living near the Kawamura sushi restaurant—and Yamabuki first-year Taichi Dan. Dan idolized Akutsu's strength, leading to an unexpected mentorship where Akutsu urged Dan to grow stronger. Akutsu also held profound loyalty for his mother, Yuuki, a single parent who had him in her teens. This loyalty compelled him to reluctantly join the U-17 training camp after she painstakingly reconstructed an invitation he had shredded.

Initially recruited for Yamabuki's tennis team by coach Mikiya Banda with the promise of chances to "hurt others," Akutsu leveraged his flexibility for high-speed shots targeting opponents. However, after his first loss to Ryoma Echizen in the prefectural tournament, he quit tennis, feeling both satisfied and bored. Coach Banda persistently persuaded him to return, which he did by the U-17 camp. There, he demonstrated significant growth, becoming one of the first middle schoolers capable of hitting ten balls simultaneously in drills. He later formed an effective doubles partnership with Genichiro Sanada, their contrasting styles—Sanada's discipline versus Akutsu's unpredictability—proving complementary.

Selected as an Aggressive Baseliner for the Japan U-17 World Cup team's original middle school roster, Akutsu competed in the group league against Switzerland. Facing Alexander Amadeus in Singles 3, he adopted a strategy of absorbing the full impact of Amadeus's powerful shots instead of evading them. This resulted in visible injuries, including bleeding that stained his sneakers red—interpreted by teammates as atonement for his past violent court behavior. He lost the match 1-6. Bound by a pre-match agreement with captain Byoudouin Hoo requiring immediate departure upon loss, Akutsu was replaced by Yamabuki teammate Kiyosumi Sengoku and returned to Japan. Before leaving the camp, he intervened to protect Kawamura from the force of Gin Ishida's shots during a match, catching him when launched toward the seats.