Carbon steel · ProterialShirogami #3 白紙3号
Also called: White #3 · Shiro #3 · White paper steel #3
Shirogami #3 is a non-stainless carbon steel from Proterial (formerly Hitachi Metals): 0.80–0.90% carbon, no chromium, and a maker hardening hardness of HRC ≥60 water-quenched; ≥52 oil-quenched and tempered at 280–340 °C.
Composition
| C | Si | Mn | P | S |
|---|---|---|---|---|
| 0.80–0.90 | 0.10–0.20 | 0.20–0.30 | ≤0.025 | ≤0.004 |
Mass %. As published by the steelmaker (typical or representative values). Hardness: ≥60 water-quenched; ≥52 oil-quenched and tempered at 280–340 °C.
What the data says
Shirogami #3 has the least carbon of the White family: 0.80–0.90%. Proterial rates it “middle hardness” and lists two heat treatments: at least 60 HRC when water-quenched, or at least 52 HRC when oil-quenched and tempered at 280–340 °C.
That second, softer treatment is a reminder that the same steel can be made into very different tools; the maker lists kitchen knives and saws among its uses. The hardness of a finished knife depends on how the knifemaker heat-treats it.
With no chromium, it rusts like the other White steels and benefits from being dried promptly.
Shirogami #3 compared with similar steels
| Steel | Type | C % | Cr % | Maker HRC | CATRA mm |
|---|---|---|---|---|---|
| Shirogami #3 | Carbon | 0.80–0.90 | — | ≥60 water-quenched; ≥52 oil-quenched and tempered at 280–340 °C | — |
| Shirogami #2 | Carbon | 1.05–1.15 | — | ≥60 | — |
| Shirogami #1 | Carbon | 1.25–1.35 | — | ≥60 | — |
| AUS-8 | Stainless | 0.70–0.80 | 13.00–14.50 | 59 (reference value) | — |
Detailed comparison: Blue vs White steel
See all 15 steels in the Japanese knife steel chart, or compare up to three at once in the steel explorer.
Care
Shirogami #3 is not stainless. Wipe the blade dry after use; a grey or blue patina is normal, but orange spots are rust and should be removed early.
Buying a Shirogami #3 knife from a shop in Japan? Japanese kitchen knives currently pay about 31% US import duty — use the import duty calculator to compare with a US retailer.
Frequently asked questions
- Is Shirogami #3 stainless?
- No. Shirogami #3 has no chromium in the maker’s composition, while a stainless steel needs roughly 10.5% or more, so it can rust if left wet.
- How hard is Shirogami #3?
- Proterial publishes a hardening hardness of HRC ≥60 water-quenched; ≥52 oil-quenched and tempered at 280–340 °C. The hardness of a finished knife depends on the knifemaker’s heat treatment.
- Who makes Shirogami #3?
- Shirogami #3 is made by Proterial (formerly Hitachi Metals).
- Shirogami #3 vs Shirogami #2: what is the difference?
- Shirogami #3: C 0.80–0.90%, no Cr, maker hardness HRC ≥60 water-quenched; ≥52 oil-quenched and tempered at 280–340 °C. Shirogami #2: C 1.05–1.15%, no Cr, maker hardness ≥60 HRC.
Sources
Checked 2026-10-21. Found a better source or an error? Tell us.