HAP40 is a powdered high-speed semi-stainless steel from Hitachi Metals, and it has earned a devoted following among serious cooks for one reason above all others: edge retention that is simply in a different category from anything else. Kitchen knives made from HAP40 hold their edge three to five times longer than traditional carbon or stainless steels. At 65-66 HRC, it is harder than Aogami Super, harder than SG2, and fine-grained enough to take a screaming sharp edge and get it back easily on quality water stones. CKTG has been calling it Voodoo Steel for years - and anyone who has used it understands why.
The nakiri is Japan's dedicated vegetable knife, with a flat edge, a tall blade, and a squared tip, it is built entirely for push-cutting produce. HAP40 in a nakiri is a remarkable combination - the edge retention that makes the steel famous deployed in the knife format that benefits most from not having to sharpen mid-service. The thin grind lets the blade pass through food with minimal resistance, and the 60/40 asymmetric edge, biased right, works equally well for right- and left-handed cooks. Stainless san-mai cladding over the HAP40 core keeps daily maintenance straightforward. The octagonal brown-black oak handle is well balanced for board work (trust the photos for the current version; the video below shows the older handle). CKTG is the only source for the Kohetsu HAP40 line.
What Customers Are Saying: Reviewers consistently describe this nakiri as extremely sharp right out of the box, with several passing the newspaper test on delivery. More than one reviewer mentioned that while the factory edge is impressive, taking it to a proper set of water stones unlocks noticeably more performance, bringing the blade to a mirror finish beyond what it ships with.
Care Instructions: HAP40 is a semi-stainless steel - the stainless cladding fully protects the flanks and the HAP40 core has meaningful corrosion resistance, but hand washing and drying after each use is still best practice. Avoid the dishwasher. HAP40 at 65-66 HRC is harder than most kitchen steels - use wood or rubber cutting boards only and avoid bones, frozen foods, and hard materials that could chip the edge. Sharpen on quality water stones; HAP40 sharpens more easily than most powdered steels but rewards patience and consistent angle. Strop regularly between sharpenings to maintain peak performance.Brand: Kohetsu
CKTG Exclusive - Available Only at CKTG
Blacksmith: Tsukahara Family
Location: Seki City, Japan
Construction: Laser Cut, San Mai
Edge Steel: HAP40 Semi Stainless (Powdered High Speed Steel)
Cladding: Stainless Steel
HRC: 65-66
Edge Grind: 60/40 Asymmetric Double Bevel
Etching: Acid Etched Kanji
Handle: Octagonal Brown-Black Oak Wood (photos are current)
Weight: 5.0 oz (144 g)
Blade Length: 165 mm
Total Length: 317 mm
Spine Thickness at Base: 2 mm
Blade Height: 47 mm
The nakiri is Japan's dedicated vegetable knife, with a flat edge, a tall blade, and a squared tip, it is built entirely for push-cutting produce. HAP40 in a nakiri is a remarkable combination - the edge retention that makes the steel famous deployed in the knife format that benefits most from not having to sharpen mid-service. The thin grind lets the blade pass through food with minimal resistance, and the 60/40 asymmetric edge, biased right, works equally well for right- and left-handed cooks. Stainless san-mai cladding over the HAP40 core keeps daily maintenance straightforward. The octagonal brown-black oak handle is well balanced for board work (trust the photos for the current version; the video below shows the older handle). CKTG is the only source for the Kohetsu HAP40 line.
What Customers Are Saying: Reviewers consistently describe this nakiri as extremely sharp right out of the box, with several passing the newspaper test on delivery. More than one reviewer mentioned that while the factory edge is impressive, taking it to a proper set of water stones unlocks noticeably more performance, bringing the blade to a mirror finish beyond what it ships with.
Care Instructions: HAP40 is a semi-stainless steel - the stainless cladding fully protects the flanks and the HAP40 core has meaningful corrosion resistance, but hand washing and drying after each use is still best practice. Avoid the dishwasher. HAP40 at 65-66 HRC is harder than most kitchen steels - use wood or rubber cutting boards only and avoid bones, frozen foods, and hard materials that could chip the edge. Sharpen on quality water stones; HAP40 sharpens more easily than most powdered steels but rewards patience and consistent angle. Strop regularly between sharpenings to maintain peak performance.
