Pattern welding is a blacksmithing technique in which several bars or layers of iron and steel of differing composition are forge-welded together, twisted, folded and hammered out to form a single blade or object. When the finished surface is polished and lightly etched, the different metals react in contrasting tones, revealing swirling, banded or herringbone patterns running through the steel.
The method was used across Europe from the Roman period onwards and reached a high level in the sword blades of the Migration period and the Viking age, when it combined toughness with a striking appearance. It is often confused with true Damascus or wootz steel, which is a crucible steel whose pattern arises from its crystalline structure rather than from welding separate layers, although the two terms are frequently used loosely in the trade. Pattern welding was later revived for gun barrels, where twisted iron and steel rods produced fine figured barrels on many nineteenth-century sporting guns, and it remains popular with modern bladesmiths. Collectors examine the clarity and evenness of the pattern, the absence of flaws or open welds, and whether any etching is original or a later enhancement.
