Laminated steel blade in the context of "Pattern welding"

Pattern welding is a smithing practice of folding and/or twisting metal, possibly multiple pieces (which may have differing compositions, or be completely different types of metal) that are forge-welded. This results in differing layers in a pattern, hence the name. This process was independently discovered by many ironworking societies. Often wrongly called Damascus steel, blades forged in this manner display bands of slightly different patterning along their entire length. These bands can be highlighted for cosmetic purposes by proper polishing or acid etching. Pattern welding was an outgrowth of laminated or piled steel, a similar technique used to combine steels of different carbon contents, providing a desired mix of hardness and toughness. Pattern welding also, more importantly, reduces impurities and, most importantly, homogenizes the steel. However modern steelmaking processes negate the need to blend different steels, reduce impurities, or homogenize the steel, pattern welded steel is still used by custom knifemakers for the cosmetic effects it produces. It is also used with non-steel metals, for its aesthetic properties, such as with mokume-gane.

A Japanese kitchen knife is a type of kitchen knife used for food preparation. These knives come in many different varieties and are often made using traditional Japanese blacksmithing techniques. They can be made from stainless steel, or hagane, which is the same kind of steel used to make Japanese swords. Most knives are referred to as hōchō (Japanese: 包丁/庖丁) or the variation -bōchō in compound words (because of rendaku) but can have other names including -ba (〜刃; lit. "-blade") and -kiri (〜切り; lit. "-cutter"). There are four general categories used to distinguish the Japanese knife designs:

1. handle — Western v. Japanese construction, or a fusion of the two
2. blade grind — single bevel, kataba v. double bevel, ryōba (outside of kitchen knives, these can mean single/double edged)
3. steel — stainless v. (high) carbon
4. construction — laminated v. mono-steel