A highly skilled Mugai-ryu killer. Little is known about his past or reasons for being sentenced to death, though it's suggested that it might involve his sick son, Tojiro, who suddenly dies. Giichi is also one of the most skilled fighters in the series, having killed a total of 59 Itto-ryu swordsmen on his own. Of the Mugai-ryu, he is the only member who manages to garner enough kills to earn his freedom. He works closely with Kagimura Habaki and cares for the other Mugai-ryu, attempting to buy Hyakurin's freedom as well, unsuccessfully. He disappears when Habaki dissolves the Mugai-ryu and is later found living in among the burakumin by Rin and Hyakurin, where he provides Rin with information concerning Manji's whereabouts. Now a broken man, he deliberately distances himself from Hyakurin to keep her from suffering any more pain and is aware of her pregnancy - when she tries to kill her baby, he stops her and persuades her to carry the child to term and allow him to raise the baby after it is born.
He uses a unique weapon which resembles an oversized bladed handcuff attached to a length of chain. The weapon, Kanetsura's Mito-no-Kami (Guardian of the Three Paths), was adapted from a thresher or similar farming implement, and allows him to sever or entangle limbs, necks and weapons from a distance. It is hard to block as the handcuff like action will wrap it around what it hits, but is broken by Manji in Volume 14: Last Blood. Giichi's first appearance is in Dark Shadows part 1.