沸出来  (Nie-deki)

What is Nie-deki in Japanese Katana terminology?

Nie-deki refers to a type of blade pattern (Hamon) in Japanese swords. ""沸"" (Nie) refers to the large, white crystals that appear in the blade pattern (Hamon) and can be identified with the naked eye. Among the blade pattern (Hamon)s that appear in swords, those with a strong Nie are called ""沸出来"" (Nie-deki).

The patterns created by the action of Nie are various, including the following:

""ほつれ"" (Hotsure) refers to the frayed Nie that appears within the edge of the straight blade (Suguha), resembling torn fabric.

""打除け"" (Uchinoke) refers to the small, crescent-shaped Nie that appear on the blade edge.

""二重刃"" (Nijuba) refers to the Nie that appear parallel to the straight blade, characterized by the appearance of a double-edged blade.

""稲妻"" (Inazuma) refers to the thin, linear streaks that appear within the tempered edge, named for their resemblance to lightning.

""金筋"" (Kinsuji) refers to the thick, linear streaks that follow the forging pattern, resembling a pattern of straight lightning.