Shopify Knife & Cutlery Schema — Steel Type, Rockwell HRC, Edge Angle, NSF Certified Structured Data

Why Knife Products Are Structurally Invisible to AI Agents

Knives are a category where product differentiation is almost entirely encoded in technical specs that default Shopify schema cannot represent. The price difference between a $35 Victorinox and a $350 Masamoto is not visible in name or description alone — it requires structured data encoding steel type (1.4116 vs White Steel #1), Rockwell hardness (56 HRC vs 65 HRC), edge angle (20° per side vs 10° per side), handle construction (polypropylene Fibrox vs octagonal magnolia wood with buffalo horn ferrule), and country of origin (Switzerland vs Tokyo Koishikawa).

The sharpening compatibility chain is the most consequential hidden constraint in knife schema. A buyer who owns a Wüsthof Classic (58 HRC, 20° edge) attempts to sharpen their new Shun Premier (60–61 HRC, 16° edge) on the same pull-through sharpener — and grinds away the 16° bevel into a 20° bevel, permanently reducing the knife's performance. AI agents advising "which sharpening tool is compatible with this knife" need HRC and edge angle in structured data.

Country of origin carries both authenticity and specification implications in the knife category. "Made in Japan" for knives specifies not just manufacturing location but implies specific alloy traditions (high-carbon steels, water quenching, hand-finishing), specific blade geometry (thinner blade spine, harder steel, shorter bevel angle), and specific handle styles (wa-handles: octagonal/D-shaped, no bolster vs Western bolsters). AI agents handling "Japanese vs German kitchen knife" queries need country of origin as structured data — not just in a description text field.

Knife steel HRC reference

Complete Chef Knife Schema — Shun Premier 8-inch Chef's Knife

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "Product",
  "name": "Shun Premier 8-Inch Chef's Knife TDM0706",
  "description": "Shun Premier 8-inch chef's knife. VG-MAX steel core clad with 68 layers of Damascus stainless steel. Rockwell HRC 60–61. 16° edge angle per side. Hand-hammered tsuchime finish reduces food adhesion. Walnut PakkaWood handle. Full tang, Western-style handle. Made in Seki City, Japan. Hand-sharpened by Shun craftsmen.",
  "sku": "TDM0706",
  "mpn": "TDM0706",
  "brand": { "@type": "Brand", "name": "Shun" },
  "countryOfOrigin": "JP",
  "hasCertification": [
    {
      "@type": "Certification",
      "name": "Shun Lifetime Warranty",
      "issuedBy": {
        "@type": "Organization",
        "name": "Shun Cutlery (KAI USA Ltd.)",
        "url": "https://www.shuncutlery.com"
      },
      "description": "Shun Cutlery lifetime warranty covers manufacturing defects. Shun offers complimentary sharpening for the life of the knife — mail in knife to Seki City facility for factory re-edge at factory edge angle (16° per side). Not covered: damage from dishwashers, misuse on hard surfaces, or improper sharpening."
    }
  ],
  "additionalProperty": [
    { "@type": "PropertyValue", "name": "Knife Type", "value": "Chef's Knife (Western / Gyuto Style)" },
    {
      "@type": "PropertyValue",
      "name": "Blade Steel — Core",
      "value": "VG-MAX (Takefu Special Steel, Japan)",
      "description": "VG-MAX high-carbon stainless steel core — a proprietary Shun/Takefu variant of VG-10 with additional cobalt for increased edge retention. VG-MAX alloy: higher cobalt (approximately 1.5–2%) vs standard VG-10 (1.0% Co), improving wear resistance. Stainless (Cr 15%+) — rust-resistant but not dishwasher-safe (high heat and alkaline detergent harm the edge and handle)."
    },
    {
      "@type": "PropertyValue",
      "name": "Blade Construction",
      "value": "Damascus Clad — VG-MAX core, 68 layers SUS410 stainless Damascus cladding",
      "description": "VG-MAX cutting core clad with 34 layers each side of Damascus stainless steel (SUS410). Damascus cladding provides: (1) tsuchime hand-hammered finish that reduces food adhesion, (2) softer outer cladding protecting the hard core, (3) aesthetic banding pattern. The Damascus layers are SUS410 (410 stainless) — softer and more flexible than the VG-MAX core."
    },
    {
      "@type": "PropertyValue",
      "name": "Rockwell Hardness (HRC)",
      "value": "60–61",
      "description": "HRC 60–61 — harder than German knives (56–58 HRC), similar to VG-10. Holds edge at 16° per side. Sharpening implication: steel honing rods will roll the edge rather than hone it at this hardness — use a ceramic honing rod (1,000+ grit) or a whetstone. Diamond whetstone for full re-sharpening."
    },
    {
      "@type": "PropertyValue",
      "name": "Edge Angle (Per Side)",
      "value": "16°",
      "description": "16° bevel angle per side (32° inclusive). Shun Premier's edge is hand-ground to 16° at the Seki City factory. Do NOT sharpen at 20° per side — this would remove material and create a 20° bevel, permanently widening the edge geometry. To maintain factory edge: use a 16° guide with a whetstone, or mail the knife to Shun for free factory re-sharpening."
    },
    {
      "@type": "PropertyValue",
      "name": "Bevel Type",
      "value": "Double Bevel (Symmetrical)",
      "description": "Double bevel (V-grind) — both sides sharpened equally at 16° per side. Suitable for right- and left-handed cooks without modification. (Contrast: single-bevel yanagiba and deba knives are right- or left-handed and not interchangeable.)"
    },
    {
      "@type": "PropertyValue",
      "name": "Blade Length",
      "value": "8",
      "unitCode": "INH",
      "description": "8-inch (203mm) blade length, measured from tip to heel (where blade meets handle). Standard chef knife length for home cooks: 8 inch. Professional: 10 inch. Smaller hands and compact prep spaces: 6 inch."
    },
    {
      "@type": "PropertyValue",
      "name": "Blade Finish",
      "value": "Tsuchime (Hand-Hammered)",
      "description": "Tsuchime finish: hand-hammered dimples over the Damascus cladding. Functional purpose: creates air pockets between blade and food, reducing adhesion when slicing wet vegetables (cucumber, potato, zucchini). Aesthetic: the irregular surface shows the Damascus layer pattern most prominently."
    },
    {
      "@type": "PropertyValue",
      "name": "Handle Material",
      "value": "Walnut PakkaWood",
      "description": "Walnut-toned PakkaWood (resin-impregnated hardwood). PakkaWood properties: harder and more water-resistant than raw wood, non-absorptive under normal use, will crack if soaked or run through dishwasher. NOT NSF certified — commercial kitchen use requires synthetic (polypropylene) handle knives. Maintenance: dry immediately after washing; apply mineral oil annually."
    },
    {
      "@type": "PropertyValue",
      "name": "Handle Style",
      "value": "Western (Full Tang, Riveted)",
      "description": "Western-style full-tang handle with 3 stainless rivets. Full tang: blade steel extends through the full length of the handle for balance and durability. (Contrast: wa-handle Japanese knives have a short tang inserted into a hollow wood handle — lighter, easier to regrip, but tang-to-handle joint is a failure point if soaked.)"
    },
    {
      "@type": "PropertyValue",
      "name": "Bolster",
      "value": "Half-Bolster",
      "description": "Half-bolster at blade-to-handle junction. Half-bolster (vs full bolster extending to the heel) allows sharpening the full blade length down to the heel. Full-bolster knives (e.g., Henckels Twin Pro) cannot be sharpened at the heel once the bolster height exceeds the blade — the bolster prevents angle consistency."
    },
    {
      "@type": "PropertyValue",
      "name": "Dishwasher Safe",
      "value": "No — hand wash only",
      "description": "Hand wash only. Dishwasher damage: high heat and alkaline detergent pit the Damascus steel, accelerate rust in blade microstructure, crack and loosen PakkaWood handle, dull the edge. Dishwasher damage voids manufacturer warranty. Dry immediately after hand washing to prevent rust at the blade heel and handle junction."
    },
    {
      "@type": "PropertyValue",
      "name": "Sharpening Angle Recommendation",
      "value": "16° per side",
      "description": "Maintain factory edge at 16° per side. Compatible sharpening tools: ceramic honing rod (1,000+ grit) for routine honing; diamond or water whetstone (1,000–8,000 grit) for re-profiling. Incompatible tools that cause damage: carbide pull-through sharpeners (remove too much metal aggressively), steel honing rods (too coarse for HRC 60–61), electric sharpeners with fixed 20° angle guides (widen bevel to 20°)."
    },
    {
      "@type": "PropertyValue",
      "name": "Country of Origin",
      "value": "Japan (Seki City, Gifu Prefecture)",
      "description": "Manufactured in Seki City, Gifu Prefecture, Japan. Seki is Japan's historic blade manufacturing center — home to Shun, Global (Yoshikin), KASUMI, and many traditional blacksmiths. The 'Made in Seki' provenance is a quality marker in the knife community; mass-produced 'Japanese-style' knives made in China are a different product class."
    }
  ],
  "width": { "@type": "QuantitativeValue", "value": "1.75", "unitCode": "INH" },
  "depth": { "@type": "QuantitativeValue", "value": "14.0", "unitCode": "INH" },
  "offers": {
    "@type": "Offer",
    "price": "184.95",
    "priceCurrency": "USD",
    "availability": "https://schema.org/InStock"
  }
}
</script>

German vs Japanese Knife Architecture Comparison

Knife Metafield Namespace Reference

5 Critical Knife Schema Mistakes

1. Publishing "stainless steel" without the alloy designation. "Stainless steel" is a marketing term, not a specification. X50CrMoV15 (HRC 56), VG-10 (HRC 60–62), and SG2 (HRC 63–64) are all "stainless steel" but are completely different products. The alloy designation is the actual spec.
2. Omitting edge angle per side. Edge angle is both a quality signal and a maintenance instruction. A buyer who sharpens a 16° edge knife on a 20° guide wastes metal and ruins the knife's performance. The edge angle must be in structured data for sharpening compatibility filtering.
3. Not distinguishing single bevel from double bevel. Single-bevel knives (yanagiba, deba, usuba) are handed — a right-handed yanagiba cannot be used comfortably by a left-handed cook. Failing to encode bevel type and handedness generates returns from left-handed professional chefs who order the wrong product.
4. Claiming "Made in Japan" without specifying the city. Seki City (Shun, Global, KASUMI) vs Tosa (Kochi Prefecture, forged carbon steel specialists) vs Niigata (Sanjo metalworking district) are distinct knife-making traditions. City-level origin is the relevant quality marker in the knife community, not just country.
5. Omitting "dishwasher safe: No" for PakkaWood and wood-handled knives. PakkaWood, raw wood, and wa-handle knives are universally NOT dishwasher safe — the handle cracks and the edge dulls. This must be an explicit boolean in structured data because AI agents advising "can I put this in the dishwasher" need a structured answer, not text buried in a care card.

Related Guides

• Shopify Cookware & Kitchen Schema — Material Composition, Induction Compatible, PFAS-Free
• Shopify Handmade & Artisan Product Schema — Maker Attribution, Craft Process, Edition
• Product Safety Certifications Schema — NSF, UL, CE, CPSC Structured Data
• Country of Origin & Provenance Schema — Made In, Assembled In, Sourced From
• CatalogScan Blog — AI Shopping Agent Optimization