Within the world of Japanese arms and armor, the sword is probably one of the most famous subjects related to art history of Japan. The forger's art has a long tradition, which can be divided in several eras starting with the Koto era. This era also referred to as "old sword era" has lasted until 1596 and is dominated by five schools/traditions of sword manufacture (gokaden) : Yamashiro, Bizen, Yamato, Sagami and Mino (named after the provinces of manufacture).

Due to the evolution of economic activity, sword forgers did no longer stay in their region. They moved to important economic centres or worked under patronage of Daimyo (regional military rulers), which lead to new forging developments. Indeed, old provincial styles could no longer be distinguished and a "new sword era" referred to as "Shinto" was introduced. The Shinto period lasted until the end of the 18th century (+/- 1780). Major changes during this period were the abandonment of the tachi and the introduction of the daisho pair of swords.

After 1780 we see a come back of old traditional Kamakura styles. This evolution is the beginning of a new era called "Shinshinto" (new-new sword era) which lasted until the abolition of sword wearing in 1876 (Haitori edict). Sword smiths reoriented their activity into other metalworking handicrafts. After the Sino (1894-95)- and Russo (1904-05)-Japanese wars, the forging of Japanese blades revived again. These swords are called "Gendaito" or modern swords and were especially made for Japanese officers. Swords made after 1945 are considered as "Shinshaku" or newly made swords.