What is Sugukuzureba in Japanese Katana terminology?
Sugukuzureba refers to a type of blade pattern (Hamon) in Japanese swords. It is a variation of "直刃調" (Suguhacho), where the blade pattern (Hamon) is straight. In "直崩れ刃", the blade pattern (Hamon) naturally collapses into the blade or the ground during tempering, and the "沸" (Nie: large particles that form a pattern on the blade when it is tempered) and "匂" (Nioi: a pattern formed by smaller particles than Nie) do not form a straight line. Despite the tight "匂口" (Nioiguchi: the boundary between the blade pattern (Hamon) and the ground iron), the lines overlap and intersect, and small feet and leaves are scattered. This is a characteristic seen in the works of "長船清光" (Osafune Kiyomitsu) and "祐定" (Sukesada), among others.