Automatic Knife Release Form
Damascus, Tsuchime, and San Mai Edge
Shun’s Damascus is formed by layering different types of metal alloys together, then forging them into a single piece. The process and the different characteristics of the layered metals create the rippling patterns you see on the blade. The number of layers can vary; many Shun knives, for example, have 34 layers of metal on each side of a high-performance VG-MAX cutting core.
As Shun artisans grind each Damascus-clad blade from its thickest point at the spine to its razor-sharp cutting edge, they reveal the patterns. To bring them out even more, they bead blast or acid etch each blade. Bead blasting also provides surface textures to help food release from the blade and reduce cutting drag. During acid etching, the layered metals react to the solution in different ways. For example, carbon steel darkens, while nickel silver remains bright. The alternating layers of darker and brighter metal help reveal the flowing, rippled pattern.
Damascus looks beautiful, supports and protects the hard, dense cutting core, and adds stain resistance. In Japan, this style of blademaking is known as kasumi. Kasumi means “mist” and is so called because the exterior Damascus can have a lovely misty appearance when compared to the harder cutting core. Kasumi construction provides the ultimate mix of properties: an extremely sharp edge and ease of sharpening.
In Japanese, tsuchime (Tsoo-CHEE-may) simply means “hammered” and you will see actual hammer marks on a tsuchime-finished blade. This finish does two things: gives the knife a look that is reminiscent of the handcrafting techniques of ancient Japan; and it creates tiny pockets of air that act as hollow-ground cavities to reduce drag and quickly release food from the blade. Shun’s gorgeous Premier line features a hand-hammered tsuchime blade finish as do some of our exclusive lines. In the tradition of ancient Japanese knife and swordmaking, Shun's tsuchime finish is created by hand hammering each blade.
San mai is a traditional, high-end Japanese blade-making technique in which a very hard steel blade core is clad with a single layer of “softer” steel on each side of the core for support and protection against corrosion. In Shun’s Sora series, the lower section of the blade—the cutting edge—is san mai with a VG10 cutting core.