Uchinoke (打除け) is a term used in the context of Japanese swords. It refers to an arc-shaped feature that appears along the edge of the blade. This feature is often seen in works with straight grain pattern (Masame-hada) or straight temper pattern (Suguha).
A representative work that features ""Uchinoke"" is the ""Mikazuki Munechika"" (三日月宗近), a famous Japanese sword. The name ""Mikazuki"", which translates to ""crescent moon"" in English, is said to have been derived from the crescent moon-like appearance of the ""Uchinoke"" feature on the blade.
In more detail, ""Masame-hada"" refers to the grain pattern on the blade that appears as straight lines running parallel to the length of the blade. This pattern is a result of the folding and forging process in sword making. On the other hand, ""Suguha"" refers to the temper pattern that appears as a straight line along the cutting edge of the blade. This pattern is a result of the differential hardening process in sword making.
Therefore, ""Uchinoke"" adds a unique and beautiful visual effect to the blade, enhancing its overall aesthetics and value."