, commonly known as , was a famous swordsmith who founded the Muramasa school and lived during the Muromachi period (14th to 16th centuries) in Kuwana, Ise Province, Japan (current Kuwana, Mie). In spite of their original reputation as fine blades favored by the shōgun Tokugawa Ieyasu and his vassals, the katana swords made by Muramasa gradually became a symbol of the anti-Tokugawa movement. Furthermore, in lore and popular culture from the 18th century, the swords have been regarded as . Work Style Much like his unique reputation, Muramasa is known for some fairly unusual features in his work. These attributes are often called by terms prefixed with "Muramasa". —The first particular characteristic of his is the frequent use of a wave-shaped hamon. The of Muramasa is categorized as , that is, it forms randomized wave-like shapes. In particular, Muramasa's has very long, shallow valleys between a cluster of shapes. Furtheremore, the front pattern and the back one often coincide well. In regards to hataraki, or metallurgical patterns created through the differential heating and quenching process, his hamon are extremely clear cut with defined nioi. Muramasa's hamon are also known to be near exact symmetrical duplicates of one another, said to be extremely intricate and difficult in the process of the hamon creation process. —The other easily identifiable feature one will see on Muramasa blades is the fish-belly (tanagobara) shape of the nakago. in the 19th century often simulated this style. Notable works Although the school of Muramasa is extremely famous in popular culture, none of their swords is designated as a National Treasure or an Important Cultural Property. is the only sword officially designated as an . Katana, length 66.4 cm, curvature 1.5 cm, bottom width 2.8 cm, , , and (see also Glossary of Japanese swords). The front side contains a sign of Muramasa and a mantra sign (a mantra from Namu Myōhō Renge Kyō or the Lotus Sutra of Nichiren Buddhism). The back side contains a year sign 永正十年葵酉十月十三日 (13th day of the 10th month of Eishō 10, that is, 10th of November, 1513). It is highly probable that the date was chosen because the high priest Nichiren died on the 13th day of the 10th month of Kōan 5 (1282). Both sides contain beautiful engravings of Kurikara (Fudō Myō-ō's mythological sword empowered by a burning dragon). The style of the engravings is similar to those of