Movie
Description
Hyūma Hoshi is the son of Ittetsu Hoshi, a former Yomiuri Giants third baseman whose career ended from a World War II injury. From early childhood, Hyūma endured relentless baseball training under his father's strict direction. This regimen forcibly converted him from right-handed to left-handed pitching using specialized equipment like the "Dai League Ball Training Cast," combined with psychological pressure and physical discipline. Marked by poverty after his mother's death and his sister Akiko assuming maternal duties, this upbringing initially bred resentment toward baseball and his father.

At Seiun High School, Hyūma formed a battery with catcher Chūta Ban, propelling the weak team to the Kōshien National Championship finals. In the semi-finals against Kumamoto Norin High School, a broken bat from Hōsaku Samon struck Hyūma's left thumb, causing a significant injury. Despite this, he pitched the championship game with a "blood-stained ball" but lost to Kōyō High School, led by rival Mitsuru Hanagata. After the tournament, Hyūma accepted wrongful implication in an attack against Chūta's father, Daizō Ban. To protect the team and the real culprit, he accepted expulsion, temporarily fracturing his friendship with Chūta.

Joining the Yomiuri Giants after leaving Seiun, Hyūma inherited manager Tetsuharu Kawakami's retired jersey number 16. Early success leveraged his exceptional "needle-through-the-hole" control. However, his small stature resulted in pitches lacking weight ("lightness"), a flaw exploited by professional batters. To compensate, he developed the "Dai League Ball" series: The No. 1 curveball intentionally aimed at the bat's weakest point, created through boxing, kendo, and marksmanship training; it required extreme concentration causing rapid fatigue. Mitsuru Hanagata countered it, leading Hyūma to refine it to target the bat's grip end. The No. 2 was a "disappearing" pitch. The No. 3 avoided bats, later causing self-destructive tendencies.

Hyūma's professional career featured intense rivalries: Confrontations with Mitsuru Hanagata peaked when Hanagata homered off the Dai League Ball No. 1, though sustaining severe muscle damage. Hanagata later defeated the improved version by holding his bat horizontally to guide the ball. After Hōsaku Samon struggled against the Dai League Ball and fell into despair, Hyūma intervened to rescue him from a false accusation. This indirectly led to Samon's marriage to Kyōko, a delinquent leader Hyūma deliberately alienated to preserve their relationship.

Hyūma suffered a career-ending injury permanently damaging his left arm, forcing his disappearance from baseball. He retrained as a right-handed pitcher, developing "Dai League Ball Right No. 1." His return to the Giants reignited rivalries, though he faced physical limitations and the psychological toll of his father's legacy.

Personally, Hyūma's relationship with Mina Hidaka ended when she died of malignant melanoma during his career. His dynamic with Ittetsu evolved from resentment to reconciliation, acknowledging his father's flawed but unwavering commitment to his success. Enduring isolation, poverty, and loss, Hyūma transformed from a coerced participant into a self-driven athlete who embraced baseball as his identity.