Suguha Hotsure"" (直刃ほつれ) is a term used in the context of Japanese swords. It refers to a feature that appears along the edge of a straight tempered blade (Suguha). This feature appears as a thin line of Nie or Nioi that runs along the grain of the blade, resembling a frayed thread.
The term ""Suguha Hotsure"" translates to ""frayed straight blade"" in English. It is named so because the feature appears as if the straight blade is fraying or unraveling, creating a unique visual effect.
In more detail, ""Nie"" refers to the visible particles of hardened steel that appear along the cutting edge of the blade, while ""Nioi"" refers to the whitish misty appearance also along the cutting edge, which is a more subtle hardening compared to ""Nie"". Both ""Nie"" and ""Nioi"" are results of the differential hardening process in sword making.
Therefore, ""Suguha Hotsure"" adds a unique and interesting visual effect to the blade, enhancing its overall aesthetics and value.