TV-Series
Description
Itaru Saitou serves as a coaching staff member at the Under-17 tennis training camp, where his primary role is not to provide mental care but to strengthen the players' mental fortitude. His specialized function involves designing the specific match-ups between players and planning the overall training regimen to improve their play and build their psychological resilience.

Saitou possesses a distinctive and memorable appearance. He is noted for his extraordinary height, standing over seven feet or 216 centimeters tall. His long black hair is frequently tied back in a loose ponytail with long bangs framing his face, and he has dark brown eyes. His typical attire consists of a black turtleneck sweater worn under a white lab coat, which contributes to his clinical and analytical presence. His personal tastes include a preference for white and gray colors, a fondness for mille-feuille pastries, and a stated special skill in counseling, though he lists his wife as something he dislikes or is bad at. His hobbies are somewhat unconventional, including mind sports, observing ants, and daydreaming while staring at the ceiling, which he describes as part of an interest in observation.

In terms of personality, Saitou presents a complex and somewhat contradictory figure. While he may initially give the impression of a gentle or slightly clumsy mental coach, his methods reveal him to be one of the strictest trainers at the camp. He firmly believes that a player's mental strength is even more important than their actual tennis ability. To test this, he designs high-pressure situations that push the middle school players to their limits. One of his most notable tactics is instructing the players to form pairs, leading them to believe they will play doubles together, only to then announce they must compete against their chosen partner in a must-win singles match, with the loser being sent home immediately. The true purpose of this cruel exercise is to reveal which players lack the tenacity to win, thereby identifying those who have fallen behind not just in skill but in mental resolve.

Despite his harsh methods, Saitou is not without a sense of hidden opportunity. He offers the losers of these matches a second chance, leading them to a bottomless valley to climb a high mountain with only their hands, a trial designed to test their willpower and mental strength. He collaborates with Coach Nyudou, who provides special training for the losers, and has been seen silently observing players undergoing this special mission, implying the process is a planned annual event. He is also noted to be somewhat absent-minded and dotes on his daughter.

Saitou's relationships outside of the camp are hinted at through his dialogue. According to another player, Saitou frequently talks about Taro Sakaki, who is the coach of the Hyotei Tennis Club. His notable abilities are less about playing tennis and more about his psychological acumen, his skill in devising elimination matches to achieve specific training outcomes, and his expertise in counseling, which he paradoxically uses in a way that is focused on confrontation rather than comfort.