Showa period, early-mid 20th century. Dating to the period of rising in organized crime (Yakuza) in Japan which peaked in about 1906. 13 1/8” length, one-piece iron, formed as a folded fan with simulated blades. The surface is a soft brow leather-like finish. The grip pierced for a wrist cord. It could be carried unobtrusively and deliver a defensive or assassin’s fatal blow.