Short answer. Most damascus kitchen knives are sanmai knives in a patterned jacket. One hard steel does the cutting. The layered pattern sits in the cladding around it and is there to be looked at. Choose the knife by its core steel, heat treatment and grind. Choose damascus because you like the look.
One piece of steel, or three layers
A typical Western kitchen knife, most German ones included, is one piece of fairly soft steel from spine to edge.
Most good Japanese kitchen knives are built differently. A thin layer of hard steel sits between two softer layers. That is sanmai (also written san mai), "three layers". The hard core takes the edge. The softer cladding supports it, adds toughness and makes the blade easier to thin and sharpen. Takefu Special Steel, the maker of VG-10 and SG2, lists its three-layer material as the most popular for kitchen knives.
Not every Japanese knife is sanmai. Honyaki and other monosteel knives are one steel throughout, and most single-bevel knives are two layers. But pick up a good gyuto or santoku and sanmai is the likely answer.
Where the damascus is
Now add damascus. On nearly every damascus knife we sell, the pattern is in the cladding. The outer layers are themselves a stack of two or more metals, bonded by the smith or at the steel mill and etched so the layers show. The core in the middle is still one piece of one steel: VG-10, SG2 or a carbon steel such as Blue 2.
So the accurate name is damascus-clad knife, not damascus steel knife. The "33 layers" or "67 layers" on a product page counts the layers in the blade (and nearly all of them are in the cladding). Your edge is one layer.
What does the pattern do for the cut? Nothing you would feel. Take two knives from the same maker with the same core, grind and heat treatment, one in plain cladding and one in damascus. They cut the same. The pattern is for the eye. Heavy thinning or abrasive cleaning will fade it.
Damascus all the way to the edge
There are knives where the layered steel is the whole blade. In a coreless knife, two or more hardenable steels are stacked in alternating layers with no separate core, so the pattern runs right to the cutting edge. In Japan this is rare and mostly found on high-end or collector lines. One example from our range is the Hatsukokoro x Nigara Itadaki, which layers Blue 2 with White 2. Some custom smiths forge their blades this way too.
These are the knives you can fairly call damascus steel.
The barrel
Here is how I think about a blade made from two steels. A wooden barrel holds water only as high as its shortest stave. Mix two steels and, broadly speaking, the blade is held back by the weaker of the two.
Testing backs part of that. In 2023 the metallurgist Larrin Thomas tested a range of two-steel damascus billets, layered right through to the edge. Toughness, the resistance to chipping and breaking, followed the less tough steel in the mix. Adding a tougher partner did little to help. Edge retention did better than the barrel suggests: it landed between the two steels, in some pairs close to the better one. A few mixes even sliced a little longer, in one case because the softer layers wear into fine teeth at the edge. The mixes that sliced longer did so at a toughness cost. The number of layers made no clear difference to edge retention.
Heat treatment is the other limit. Every steel has its own best hardening temperature, and two steels rarely share one. A layered blade is hardened as one piece, so the smith has to find a balance point. Good makers manage this by pairing steels that harden well together. The Itadaki's Blue 2 and White 2 are close relatives.
None of this makes a coreless knife a bad knife. In my view, the layering is not where the performance comes from.
Where damascus came from
Three different things get called damascus, and they are worth keeping apart.
Pattern welding is the European one. Early smiths worked with iron that came out of the furnace uneven and in small pieces. Welding and twisting rods of iron and steel together made a sword blade out of imperfect material, and the pattern it left was prized.
Folding is the Japanese answer to the same problem. Swordsmiths folded their steel many times because the raw steel varied in carbon and carried slag and voids. Folding evened out the carbon, closed the voids and worked out some of the slag.
Wootz, the original Damascus steel, was not layered at all. It was a single crucible steel from India, and its watered pattern came from the way carbides formed inside it.
In the first two cases, layering was a way to cope with steel that was not uniform. Modern steel is clean and even straight from the mill, and folding it adds nothing to performance. What is left is the craft. A good damascus blade shows what the smith can do, and that is a fine reason to want one.
Should you buy one?
Yes, if you like how it looks. A damascus-clad knife from a good maker cuts as well as its plain sibling and is a pleasure to own. Just buy it for the right reason. Pick the core steel that suits how you cook and sharpen, check the grind, and treat the pattern as the finish it is.
Quick questions
Is a damascus knife sharper than a plain one?
No. Sharpness comes from the core steel, the heat treatment and the grind. On a damascus-clad knife the pattern is in the cladding and never reaches the edge.
Is damascus the same as sanmai?
No, but they usually come together. Sanmai is the three-layer construction. In modern layered knives, damascus describes a patterned material made of many layers. Most damascus kitchen knives are sanmai with damascus cladding.
What do "33 layers" or "67 layers" mean?
The number of layers in the blade, nearly all of them in the cladding. It describes the pattern, not the quality of the edge.
Does a damascus knife rust?
That depends on the metals, not the pattern. Stainless damascus cladding resists rust. Soft iron damascus patinas and will rust if left wet. A carbon steel core can rust at the edge under either.
Is a coreless damascus knife better?
Different rather than better. The pattern runs to the edge and the whole blade is hardenable steel. Buy one for its character and for the skill it takes to make.
Will the pattern wear off?
Not in normal use. Heavy thinning or abrasive cleaning fades it.
Sources
- Larrin Thomas, "Does Damascus Outperform Super Steels? Testing Different Combinations", Knife Steel Nerds, 13 July 2023.
- Takefu Special Steel, clad metal materials.
- J. D. Verhoeven, A. H. Pendray and W. E. Dauksch, "The Key Role of Impurities in Ancient Damascus Steel Blades", JOM, 1998.
- H. Föll, "Iron, Steel and Swords", Kiel University.
Related: Sanmai · Damascus-clad sanmai · Coreless · Monosteel · Honyaki vs monosteel