During the Edo period in Japan (1600-1868), samurai were permitted to carry two swords whenever they went out. The katana and the shorter wakizashi, or 'companion sword', which was also always worn indoors.
This blade is signed 'Hizen Kuni jū Tadayoshi' ('Tadayoshi living in Hizen Province'). The Tadayoshi school of swordsmiths was established in Hizen Province in the Edo period and continued making swords into the twentieth century. This blade was made by the eighth generation of the school. Unusually, the school was sponsored by the Nabeshima clan, whereas most swordsmiths worked on a commercial basis in the Edo period. (The Nabeshima family also had their own domain potters.)
The swords are made of the finest-grained bright steel and are prized for their minute nie (individually discernible crystals of steel on bloth the flat of the blade and the even hamon.