What type of steel is SKD?

SKD is a semi-stainless knife steel, made by Hitachi Special Steel, Japan. Carbon steels can take an exceptionally fine edge but require thorough drying after use to prevent rust and discoloration.

What is the hardness of SKD steel?

SKD steel is typically hardened to 62–64 HRC on the Rockwell C scale. Within this range, higher hardness supports finer edges and longer edge retention, while slightly lower hardness gains toughness and ease of sharpening — most premium Japanese kitchen knives target the 60–63 HRC range to balance these properties.

Is SKD steel stainless?

SKD contains 5.0% chromium. The conventional threshold for stainless classification is around 13% chromium; steels below that level will discolor or rust under typical kitchen acid/moisture exposure and are classified as carbon or semi-stainless.

Semi-Stainless Semi-Stainless Steel

Semi-stainless steels sit between carbon and full stainless. They will rust if left wet or neglected, but under normal use they tend to develop a patina — a dark, protective layer — rather than forming aggressive surface rust. Rinse and wipe dry after use and you will rarely have issues. Much more forgiving than true carbon steel, while still offering excellent cutting performance. Hitachi Special Steel, Japan 🇯🇵

SKD SKD合金工具鋼

Hardness

62–64 HRC

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SKD short for SKD12 also known as A2 tool steel, with about 1% of Carbon content, and only 4.5% of Chromium. It can be treated to about 63 to 64.

The SKD very much behaves like carbon steel in terms of taking a very keen edge, the food release and also super easy to sharpen; yet without the need of high maintenance. As a result it is very popular amongst professional chefs.

Yoshikane is the noteable compnay that loves the SKD.

Compare with

SKD

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5.0% 3.8% 2.5% 1.3% 0

1.0%

5.0%

0.35%

1.0%

0.7%

0.4%

0.03%

0.25%

0.5%

C — Carbon Cr — Chromium V — Vanadium Mo — Molybdenum Mn — Manganese Si — Silicon P — Phosphorus S — Sulfur Cu — Copper Ni — Nickel

Hardness 62–64 HRC

555759616365+

Steel

SKD

Frequently asked questions

What is SKD steel used for in Japanese knives?

SKD steel is a high-carbon, mid-chromium tool steel used in Japanese knives to deliver carbon-steel-like edge sharpness and ease of sharpening without the high maintenance requirements of traditional carbon steel.

This steel contains 1.0% carbon and 5.0% chromium, allowing it to be hardened to an HRC of 62–64 while maintaining a balance between edge retention and corrosion resistance. It is currently available in the K&S catalog through the Hatsukokoro x Yoshikane collaboration, with popular in-stock options including the SKD Nashiji Honesuki 150mm for $578, the SKD Nashiji Gyuto 240mm for $590, and the SKD Nashiji Sujihiki 270mm for $649. These knives are best suited for professional chefs or serious home cooks who want a keen edge and simple sharpening process but prefer not to deal with the rusting issues common to pure carbon steels.

Reviewed by K&S staff · Last updated 18 July 2026

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