The SAN range of Tamahagane knives features 3 ply stainless steel construction. The core or middle layer is V-G No.5. This layer is very hard and acts as the cutting edge. The two outside layers are made of SUS410 stainless steel. The outside layers are softer and more stain resistant than the cutting edge and actually protect the cutting edge.
The 3-ply stainless steel has an original thickness of 20 mm and is thinned by repeated rolling to a thickness of 2 mm. You might want to look at this rolling process as a modern forging technique. Also, this rolling process removes all the impurities in the steel leaving you with a very hard, very pure stainless steel. After the rolling processes, the V-G No. 5 cutting edge reaches a hardness of 58-60 degrees on the Rockwell scale and a final thickness of .65 mm. The outside layers each reach a thickness of .675 mm.
There are several different VG stainless steels. Kataoka selected V-G No. 5 stainless steel for the SAN knives, because V-G No. 5 can be hardened as hard as any of the other V-G steels but has superior edge retention. Using scientific testing equipment (CATRA), Kataoka was able to show that their knives stayed sharper longer than knives made from other VG steels.
The edge on the SAN knives is a minute, beveled edge. The angle of the edge is between 14 and 15 degrees. To appreciate the quality of the edge, you must first look at its incredible mirror polish and then try cutting with it. Kataoka has achieved the perfect balance between sharpness and strength with the SAN edge.
The SAN knives are balanced with a stainless steel weight which attaches to the tang and is visible at the heel of the handle. Not only does this add to the beauty of the SAN design, it also creates fantastic balance.
The handle is made of a rich, dark laminated wood. The handle shape is distinctive yet classic. The handle fits very comfortably in the hand. It gives you the tradition and warmth of wood without an exposed metal tang that can sometimes cause discomfort.