In swordsmithing, hamon is a visible effect created on the blade by the hardening process. The hamon is the outline of the hardened zone which contains the cutting edge. Blades made in this manner are
Example of a hamon. It is not the entire white hadori area, but a fuzzy line within the hadori. It is difficult to photograph, and to appreciate hamon, the viewer must hold the sword in his hand and change the angle of the light on the blade as he views it.
Katana, showing the hamon as the outline of the yakiba. The nioi appears faintly as the bright line following the hamon; especially visible at the tip (kissaki).
The formation of a hamon during quenching first produces a downward bend as the edge cools fast, followed by an upward bend as the rest of the blade cools.
Types of hamon. The first is a straight pattern and the remaining are various irregular patterns (gunome).
Pattern welding is a smithing practice of folding and/or twisting metal, possibly multiple pieces that are forge-welded. This results in differing layers in a pattern, hence the name. This process was
Hamon (swordsmithing)
…Glossary of Japanese swords Pattern welding Cheness Inc page about Hamons and how to differentiate fakes…
A contemporary pattern-welded sword blade made by Danish swordsmith Ejvind Nørgård. The blade shows a chevron pattern with opposing twists and straight laminate alternating.
An image of a modern pattern welded knife blade, showing the dramatic patterning on the side below, and the layering of the steel in the spine above. Acid etching darkens the 1080 plain carbon steel more than it does the 15N20 low alloy nickel steel, producing alternating bands of light and dark on the surface.