Overview: The Japanese sword, a formidable weapon now appreciated as a work of fine artisanship. The samurai particularly valued Muramasa blades. Over 400 years ago, shogun Tokugawa Ieyasu himself wielded a Muramasa as he secured his leadership over a unified Japan. But his sword was also thought cursed. The Tokugawa shoguns passed the weapon down over the generations. But why? Japanese sword expert and former British Museum curator Paul Martin explores the mystery of this legendary cursed blade.