With a scoop of a net Tokyo chef Naohito Hashimoto selects a poisonous blowfish, considered a delicacy in Japan, and with a few deft strokes of his gleaming knife starts the delicate process of preparing it for a customer. In moments, Hashimoto has separated the edible parts of the fish from organs filled with a poison more deadly than cyanide. For more than six decades, dicing blowfish in Tokyo has been the preserve of a small band of strictly regulated and licensed chefs, usually in exclusive restaurants....