Tsunoashi (角足) is a term used in the context of Japanese swords. It refers to a pattern where the ""Ashi"" - the line or dot that appears from the blade edge towards the tip - appears in two lines parallel to each other in the valley of the tempering, and opens to the left and right.
The term ""Tsunoashi"" translates to ""horn foot"" in English. It is named so because the pattern resembles the shape of a cow's horns. This feature is often seen in the works of swordsmiths from the Mino tradition.
The Mino tradition is one of the five main traditions of Japanese sword making, and it is known for its distinctive features such as ""Tsunoashi"".
Therefore, ""Tsunoashi"" adds a unique and interesting visual effect to the blade, enhancing its overall aesthetics and value.