A katana is a type of Japanese sword, historically worn by samurai and therefore also popularly referred to as samurai sword. However, a samurai often carried other swords as well, such as the wakizashi and tantō. A katana's blade is usually made in the traditional metal known as tamahagane (玉鋼), and is somewhere between two or three feet long, but is measured in the Japanese measure of shaku (尺), which equals roughly 30 cm or 12 inch.