Know your knife
Steel decides almost everything
Two knives can look identical and behave nothing alike, because the core steel under the cladding is doing most of the work. Here is what the six steels in our range actually do.
Carbon steels
Blue Super (Aogami Super)
A high-carbon, high-alloy steel with tungsten and chromium added to a Blue paper base. It takes an extremely keen edge and holds it well, and it is used in our Kurotetsu gyuto at roughly 65 HRC. It is also carbon steel: it will patina, and it will rust if left wet. Dry it after every use and it becomes more beautiful, not less.
White #2 (Shirogami)
Purer and simpler than Blue, with fewer alloying elements. It takes a very fine edge quickly on the stones and is the traditional choice for single-bevel and butchery knives, including our Ishizuchi honesuki at roughly 62 HRC. It is also the least forgiving steel in the range if neglected.
Stainless steels
VG-10
A cobalt-bearing stainless that has become the standard for Japanese home knives. Roughly 60-61 HRC, easy to sharpen, resistant to rust, and often paired with damascus cladding because it takes a clean polish. It is what most people should buy first.
Ginsan (Silver #3)
A stainless steel that sharpens and feels close to carbon on the stones, which is why professional kitchens like it. Run at roughly 61 HRC in our sujihiki. Stainless, but it rewards a proper sharpening more than VG-10 does.
Powder steels
SG2 (R2)
A powder metallurgy stainless with a very fine, uniform carbide structure. Roughly 63 HRC in our bunka, fully stainless, with noticeably longer edge life than VG-10 and a bright, toothy bite.
HAP40
A powder high-speed steel, and the most wear-resistant steel we use — roughly 66 HRC in our kiritsuke. It holds an edge for a very long time, and it takes proportionally longer on the stones when the edge finally goes. Not the steel to learn sharpening on.
What the HRC number means
Hardness, measured on the Rockwell C scale. A harder blade resists dulling, but becomes more brittle and slower to sharpen. Nothing in this range needs to go above 66; a number printed on a page is not the same as an edge that suits a kitchen.
A short decision list
- You will dry the knife after every use and want the sharpest edge available: carbon.
- You cook in a hurry and the knife sits wet on the board: VG-10 or Ginsan.
- You want to sharpen rarely and hold an edge for months: SG2 or HAP40.
- You are buying your first Japanese knife: a VG-10 santoku or gyuto.