Stainless
Stainless Steel
"Stainless" means stain-resistant, not stain-proof. In kitchen use, the steel can still discolour or pit if exposed to acidic environments — citrus, vinegar, or salt water — for extended periods. Wash and wipe dry after every use, and avoid leaving the blade soaking in water. With basic care, a stainless knife is very low-maintenance and a great everyday choice. Aichi, Japan 🇯🇵
"Stainless" means stain-resistant, not stain-proof. In kitchen use, the steel can still discolour or pit if exposed to acidic environments — citrus, vinegar, or salt water — for extended periods. Wash and wipe dry after every use, and avoid leaving the blade soaking in water. With basic care, a stainless knife is very low-maintenance and a great everyday choice. Aichi, Japan 🇯🇵
ZA-18 ZA-18ステンレス鋼
Hardness
Rockwell C Hardness(HRC) measures how resistant a steel is to permanent deformation. For kitchen knives:
55–58 HRC — Soft. Easy to sharpen and forgiving of rough use, but dulls faster. Typical of most German knives.
59–61 HRC — Balanced. Good edge retention with manageable sharpening. Common in mid-range Japanese knives.
62–64 HRC — Hard. Excellent edge retention, holds a very fine edge. Requires more care and a fine stone to sharpen.
65+ HRC — Very hard. Exceptional edge longevity but more brittle — more prone to chipping if used roughly.
Higher is not always better — it depends on how you use and maintain your knife.
55–58 HRC — Soft. Easy to sharpen and forgiving of rough use, but dulls faster. Typical of most German knives.
59–61 HRC — Balanced. Good edge retention with manageable sharpening. Common in mid-range Japanese knives.
62–64 HRC — Hard. Excellent edge retention, holds a very fine edge. Requires more care and a fine stone to sharpen.
65+ HRC — Very hard. Exceptional edge longevity but more brittle — more prone to chipping if used roughly.
Higher is not always better — it depends on how you use and maintain your knife.
60–62
HRC
555759616365+
ZA-18 steel is a premium Japanese stainless knife steel developed by Aichi Steel, designed for high-end kitchen knives. Known for its fine grain structure, ZA-18 delivers exceptional sharpness, superior edge retention, and improved toughness compared to VG10.
With high carbon content for hardness (typically 60–62 HRC) and added chromium, molybdenum, and vanadium, ZA-18 offers excellent corrosion resistance, wear resistance, and edge stability. This makes it ideal for demanding professional kitchens and serious home cooks.
Popular in Japanese chef knives, ZA-18 steel provides a perfect balance of durability, long-lasting sharpness, and easy maintenance, making it a top choice for those seeking reliable, high-performance kitchen knives.
With high carbon content for hardness (typically 60–62 HRC) and added chromium, molybdenum, and vanadium, ZA-18 offers excellent corrosion resistance, wear resistance, and edge stability. This makes it ideal for demanding professional kitchens and serious home cooks.
Popular in Japanese chef knives, ZA-18 steel provides a perfect balance of durability, long-lasting sharpness, and easy maintenance, making it a top choice for those seeking reliable, high-performance kitchen knives.
ZA-18 Composition
What's in ZA-18
What each element does in your knife.
| Element | Composition | What it does in your knife |
|---|---|---|
| CrChromium | 17.0–18.0% | Raises corrosion resistance; at roughly 13%+ free chromium the steel qualifies as stainless. Also improves hardenability and wear. |
| CoCobalt | 1.8% | Allows higher hardening temperatures for more hardness and wear resistance, and strengthens the steel matrix. |
| MoMolybdenum | 1.0–1.5% | Improves hardenability and toughness, boosts corrosion resistance, and helps the steel hold hardness under heat. |
| CCarbon | 0.95–1.2% | The primary hardening element. More carbon means a harder edge that holds longer — but past a point it trades away toughness and rust resistance. |
| SiSilicon | ≤ 1.0% | Strengthens the steel matrix and acts as a deoxidiser, improving hardness and resistance to oxidation. |
| MnManganese | ≤ 1.0% | Aids hardenability and strength and acts as a deoxidiser in smelting. Too much can reduce toughness. |
| VVanadium | 0.1–0.25% | Forms extremely hard vanadium carbides for superior edge retention, and refines the grain for a finer, tougher edge. |
| PPhosphorus | ≤ 0.04% | An impurity from smelting. Even small amounts promote brittleness, so steelmakers keep it as low as possible. |
| SSulfur | ≤ 0.03% | 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.
ZA-18 Buying Guide
Should you buy ZA-18?
Where it shines
- “Aichi's copy of the Bohler-Uddeholm N690 steel.” — per zknives
