The Tamahagane San Tsubame hand-ha-mmered knives feature 3-ply stainless steel construction. The 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 are more stain resistant then the cutting edge and actually protects the cutting edge. The original thickness is 20-mm and is then thinned by a repeated rolling process to remove all of the impurities, leaving you with very hard, very pure 2-mm stainless steel. Some view this as a modern forging technique. The final thickness of the knife blade is 0.65-mm and the outside layers are 0.675-mm which is why it reaches 61-Degree of hardness on the Rockwell scale. There are several different V-G stainless steels. Kataoka selected V-G No. 5 because it can be hardened as hard as all other V-G steels, but has superior edge retention and stays sharper longer then other knives made of V-G steels. Like the Tamahagane San Kyoto series, the edge on the San and the San Tsubame knives have minute beveled edges. The angle of the edge is between 14 and 15-Degree. To really 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 these edges. The handle is made of dark, rich laminated wood which gives the full metal tang a warm, traditional feel in your hand and an elegant look in your kitchen.