What is Yakiotoshi in Japanese Katana terminology?
Yakiotoshi refers to a type of blade pattern (Hamon) in Japanese swords. It is a term used to describe a sword where the tempered blade (Yakiba) starts from a point above the ""刃区"" (Hamachi: the notch on the edge of the blade). Normally, the tempered blade of a sword starts from the Hamachi, but in some cases, the tempering starts from a point above the Hamachi, and the Hamachi itself is not tempered.
This characteristic is particularly seen in the Tachi (a type of Japanese sword) made by ""豊後国行平"" (Bungo no Kuni Yukihira), a swordsmith active during the late Heian period to the early Kamakura period.
It is rarely seen in swords other than those that have been re-tempered, and it is only found in ""生ぶ茎"" (Ubu Nakago: original tang). Therefore, existing examples are extremely rare.