A Japanese sword that is longer than 23.6" (60cm) and is worn in the belt with the edge up is called a Katana. This conversion from Tachi to Katana probably began in the Muromachi period (1392 - ) but became widely worn in the Shinto period. It became popular to wear two swords in the thrust in the sash with the edges up. These two swords together were known as a daisho or "large and small". The smaller of the two swords was called a wakizashi.