Carbon Steel Carbon Steel

Carbon steel is reactive — it will rust quickly if not properly cared for. Always wash immediately after use, dry thoroughly, and apply a thin coat of food-safe oil (camellia, mineral) before storage. Over time it develops a patina that offers some natural protection and, for many users, becomes part of the knife's character. Rewarding to use, but not recommended if you want a "wash and forget" knife. Hitachi Special Steel, Japan 🇯🇵

White 1 / Shirogami #1 白一鋼

Hardness

62–65 HRC

555759616365+

White Steel #1, also known as Shirogami #1, stands out in the realm of high-end Japanese cutlery materials for its exceptional purity and performance. It is an advanced version of White Steel No.2, achieved through further refinement and an increased carbon content. This additional carbon allows White No.1 to attain a slightly higher hardness (HRc) than its predecessor, enhancing its ability to be sharpened to an extremely fine edge. However, this increase in carbon also introduces a bit more brittleness to the steel. Despite this, White No.1 is highly favored by professional chefs, especially those specializing in traditional Japanese cuisine, due to its superb edge retention and ease of resharpening. Unlike its Blue Steel counterparts, White No.1 lacks chromium and tungsten, focusing instead on achieving the highest possible sharpness. This characteristic, while offering unparalleled sharpness, means it is more reactive and requires careful maintenance, including prompt wiping and drying after use, to prevent corrosion.

Compare with

White 1 / Shirogami #1

—

1.3% 1.0% 0.7% 0.3% 0

1.3%

0.25%

0.15%

0.025%

0.004%

C — Carbon Mn — Manganese Si — Silicon P — Phosphorus S — Sulfur

Hardness 62–65 HRC

555759616365+

Steel

White 1 / Shirogami #1

What's in White 1 / Shirogami #1

What each element does in your knife.

White 1 / Shirogami #1 element composition and spec ranges
Element	Spec range	What it does in your knife
CCarbon	1.25–1.35%	The primary hardening element. More carbon means a harder edge that holds longer — but past a point it trades away toughness and rust resistance.
MnManganese	0.2–0.3%	Aids hardenability and strength and acts as a deoxidiser in smelting. Too much can reduce toughness.
SiSilicon	0.1–0.2%	Strengthens the steel matrix and acts as a deoxidiser, improving hardness and resistance to oxidation.
PPhosphorus	0.025%	An impurity from smelting. Even small amounts promote brittleness, so steelmakers keep it as low as possible.
SSulfur	0.004%	An impurity that reduces toughness and promotes brittleness; only ever added deliberately in free-machining steels.

Composition from zknives (K&S steel dataset) reference material. These ranges come from the K&S steel composition dataset, which is derived from zknives; maker figures are cited separately only when they are used on the page.