Kōshin Chin Sanzan is a supporting character in the OVA series Giant Robo: The Day the Earth Stood Still. He belongs to the International Police Organization, specifically its division known as the Experts of Justice, a group of elite operatives with superhuman or highly trained abilities assembled to counter the secret society Big Fire. Chin Sanzan embodies a strict, unwavering sense of honor and duty. His demeanor is gruff and humorless, a direct consequence of his absolute commitment to mission objectives. He expects orders to be followed without hesitation and does not tolerate sentimentality or reluctance in the field. This rigid sense of discipline brings him into conflict with the young protagonist, Daisaku Kusama, the master of Giant Robo. In a pivotal moment during the seventh episode, Chin Sanzan slaps Daisaku when the boy refuses to command Giant Robo to attack the Eye, a critical target, because doing so would endanger his friend GinRei. The action underscores Chin Sanzan’s belief that the larger objective must take precedence over personal bonds, even at a painful cost. His role in the story is that of a senior figure who enforces hard decisions and pushes the younger members of the team to act with resolve. While his background is not extensively detailed, his name and bearing suggest a cultural heritage rooted in classical Chinese martial tradition, and his position among the Experts indicates that he possesses formidable combat skills, likely including proficiency in hand‑to‑hand fighting or a unique supernatural technique. Throughout the series, Chin Sanzan remains a constant, unyielding presence, representing the harsh necessities of the war against Big Fire. His development is subtle; he does not soften, but his actions reveal a deep underlying sense of responsibility for the lives and outcomes entrusted to him.