A Lone Wolf in the Shadows of the Showa Era: Tōichi Mannen and the Rise and Fall of the Gurentai, 1930s–1950s

From the early Showa period through the postwar era, Tōichi Mannen was a man who stood out in Shinjuku’s underworld. Unaffiliated with any established yakuza organization, he made a name for himself through his fighting prowess and unique convictions, earning the title “the originator of the gurentai.” In 1938, he attacked Isoo Abe, the leader of the Social Masses Party, and his name became widely known. During the war, he traveled to mainland China, and after demobilization, he returned to a Tokyo reduced to rubble. In Shinjuku immediately after Japan’s defeat, gamblers, street vendors, and “guren-tai” clans were vying for control of the black market. Mannen acted as a mediator in these conflicts and as a bodyguard, becoming a figure who would later influence the underworld. Eventually, “guren-tai” clans linked to Mannen’s lineage—such as those led by Mitsugu Kano—began to rise to prominence. The postwar chaos was an era in which the traditional order collapsed while new, unofficial powers emerged. Mannen’s life was a complex interweaving of violence, anti-authoritarianism, and an obsession with freedom. By viewing him not merely as a lawless outlaw but as a figure who embodied the dark underbelly of the city—spanning from the prewar to the postwar era—the transformation of the Shōwa-era underworld comes into sharp relief.