Short version: the Miyabi Koh 240 mm sujihiki is the slicer to buy if you want the specification in writing. It is the plainest knife Miyabi makes — no Damascus, no cladding, no bolster — and that is the reason to buy it rather than a reason not to: you are paying for the Seki grind and the published numbers instead of the etch. Three things are missing from the product page, and one of them is the spec most reviews of long knives get wrong.
What ZWILLING actually publishes
The knife is item 33950-243. On its own product page ZWILLING publishes a blade of 9.45 in (240 mm, sold as “9.5-inch”), “Advanced FC61 fine carbide stainless steel” at “61 HRC”, a “9.5-12° edge angle” produced by a “Hand-honed, 3-step Honbazuke blade”, a “FRIODURx2® Ice-Hardened Blade”, an “Octagon-shaped Pakkawood handle” on a concealed tang, a weight of 0.35 lbs, “Hand wash only”, a lifetime warranty, and “Handcrafted in Seki, Japan”.
That is an unusually complete disclosure for a slicing knife, and it is the whole case for this one. Both rival 240 mm sujihikis in our registry leave the two figures that matter most blank on the maker’s own site.
The one thing this knife has that its rivals do not
It is the only 240 mm sujihiki we can point at where the maker publishes both a hardness figure and an edge angle. That sounds like a small thing. It is the entire reason a spec-first site can recommend it.
Misono publishes a size list for its Molybdenum-series sujihiki — No. 521 at 240 mm, No. 522 at 270 mm, and so on — and a series description naming “high-carbon 13-chrome stainless with molybdenum.” It publishes no Rockwell figure, no weight, no handle spec and no bevel angle. The 57 HRC, the 157 g, the 2.2 mm spine and the 70/30 bevel that circulate for that knife all come from a specialist retailer’s spec table, not from Misono. We cite that retailer by name on the product card and say which figure is whose, because the distinction is the difference between a manufacturer’s commitment and a shop’s measurement. Yoshihiro publishes nothing at all in the way of a hardness number for its hammered Damascus 240 mm.
ZWILLING commits to 61 HRC and 9.5–12° in the place a buyer will actually look. Our hardness chart sets out what that band feels like in the hand: it is hard enough to hold a genuinely acute edge for a long time, and hard enough that you must stop treating the knife like a German one.
The weight, and why it is the right weight
ZWILLING publishes 0.35 lbs — about 159 g — for a 240 mm blade. People who have only handled Western carving knives read that and assume it is a misprint. It is not, and here is the cross-check that settles it: the retailer’s spec table for the Misono No. 521, the same 240 mm class, gives 157 g. Two long slicers, two grams apart, from two unrelated makers.
That is what a sujihiki is. It carries very little blade height and it is ground thin from spine to edge, so there is barely any metal in it despite the length. The absence of mass is the feature — a thick blade has to wedge a roast apart as it passes, which drags and distorts the slice, and 159 g of thin steel simply does not do that. It is also exactly why the knife is wrong for board work, which the sujihiki guide goes into properly.
One figure we will not build an argument on: ZWILLING lists its own Koh 8-inch chef’s knife at 0.62 lbs (about 281 g), which would make this longer knife 44 percent lighter than its shorter sibling. That is a tempting headline, and we are not going to write it, because ZWILLING’s own Kaizen II 8-inch chef’s knife is listed at 0.44 lbs (about 200 g) — so at least one of those three numbers is measuring something different from the others, probably packaging. The two sujihiki figures agree with each other and with the shape; the chef’s-knife comparison does not survive scrutiny, so we are leaving it out rather than dressing it up.
The three things ZWILLING leaves off the page
- What FC61 is. ZWILLING names the steel — “FC61 fine carbide stainless steel” — and stops. It does not publish a composition, and it does not say what the alloy corresponds to. The most-cited third-party account holds that FC61 is ZWILLING’s trade name for Sandvik 13C26, itself close to Uddeholm AEB-L, a genuinely fine-carbide stainless whose measured behavior is well documented. ZWILLING has never confirmed that, so we treat it as unconfirmed everywhere it appears. The full argument, with the numbers that are measured, is in FC61 vs VG10.
- The blade geometry. The dimension block reads “Length of product: 15.12 in”, “Width of product: 0.75 in” and “Height of product: 1.30 in”. Those are not blade measurements — a 240 mm sujihiki is on the order of 2 mm at the spine — so we read them as a shipped-item figure and mark spine thickness and blade height as not published. It also means we will not do the arithmetic on handle length, because we cannot tell whether that 15.12 in is the knife or the carton.
- What to do about maintenance. ZWILLING’s page for this knife says “Hand wash only” and no more. Its general care page is where the useful detail is, and we have pulled it in below.
Plain steel, and why that is the point
Koh is Miyabi’s entry line, and it looks like it: a mirror-polished mono-steel blade, no Damascus cladding, no hammered tsuchime face, no bolster. Every visual flourish the brand is known for has been removed.
What has not been removed is the part that cuts. The same ice-hardening ZWILLING calls FRIODURx2, the same hand-honed 9.5–12° edge, the same three-step Honbazuke process — which ZWILLING describes as grinding the knife “on a coarse vertical rotating sharpening stone”, then “finely honed on a horizontal rotating sharpening stone”, then polished on “a vertical rotating leather stropping block” — and the same Seki workshops. On a slicer that is the correct set of trade-offs, because nobody is admiring the finish on a knife that spends its working life buried in a brisket. Damascus cladding is decorative; the Damascus explainer makes that case at length.
The handle is the other saving. An octagonal pakkawood handle is symmetrical, which makes it handed-neutral in a way Miyabi’s D-shaped handles are not — a genuine advantage if you are left-handed, and the reason the left-handed guide keeps pointing at octagonal handles. It sits on a concealed tang rather than the full tang most Western slicers at this money advertise. That is a normal Japanese construction and not a fault, but it is a real difference from the Misono, and our handle guide explains what pakkawood is and how long it lasts.
Living with 61 HRC on a 9.5° edge
This is a hard blade on a very acute grind, and the maintenance follows from the numbers rather than from anyone’s opinion. No grooved honing rod: at this hardness the edge does not realign when you steel it, it fractures. A fine ceramic rod or a strop covers the weeks between sharpenings, and a 1000/6000 combination stone does the real work. Not every sharpener can hold a 15° edge, let alone a 9.5° one — the sharpeners that can are a short list, and most pull-through devices are not on it.
A long, nearly straight blade is genuinely easier to sharpen than a curved chef’s knife, because there is no belly to sweep through: you set the angle once and draw. The catch is that the blade is longer than most stones, so you work in sections, and any wobble at 61 HRC takes a chip rather than rolling a burr. If you have not done this before, read how to sharpen a knife first and practice on something cheaper.
On cleaning, ZWILLING’s own care page is more specific than the product page: wash “by hand using lukewarm water, mild dish soap and a non-scratch cloth or sponge”, dry with “a plain dishtowel or microfiber cloth”, and keep it out of the dishwasher, which it blames for “aggressive chemical tablets”, “high temperatures” and “bumps and bangs with other objects”. On wooden handles it goes further: they are “not dishwasher-safe and should only be washed by hand”, and it recommends “regularly treating the wood with oil (e.g. linseed oil) or wax (e.g. beeswax)”. And a knife should have “its very own space away from other objects, so not simply thrown in the cutlery drawer” — on a 240 mm blade at this hardness, that is not fussiness. More in our knife care guide.
The warranty, and where you buy it
This is the part of the purchase most reviews skip, and it is the part we think hardest about on a page that carries a buy link.
ZWILLING’s US terms are generous on their face: a product is covered as “free of defects in material and workmanship from the date of purchase for as long as said purchaser owns the product.” Two conditions attach. The first is ordinary — “the original purchaser must provide valid proof of purchase”, and the warranty “does not cover defects resulting from normal wear and tear, misuse, abuse, alteration, negligence, or use of the product other than its intended purpose.” On a 61 HRC slicer, “intended purpose” is doing real work: this knife is for protein, not for bone, frozen food or prying.
The second condition is the one that matters on a marketplace. The warranty applies to products “purchased in the United States from Zwilling or a Zwilling authorized seller located in the United States”, and ZWILLING reserves “the right to reject warranty claims for products purchased from unauthorized sellers.” On a marketplace listing the seller is frequently not the brand, so check who the listing actually ships and sells from before you order, and treat an unusually low price as the first thing to investigate rather than the reason to click. That applies to our link as much as to anyone else’s. Our where-to-buy guide covers the channels in full.
The four things it does badly
- It is a one-job knife, and the job is narrow. A sujihiki slices protein. It has almost no blade height, so there is no knuckle clearance and no scooping a board of diced onion, and it cannot rock-chop. If you are choosing between this and a knife you would use every day, buy the every-day knife — the buying order puts a gyuto first for a reason.
- It is plain, and some people mind. A mirror-polished mono-steel blade is the least decorated thing Miyabi sells. If part of the appeal of a Japanese knife is that it is beautiful, this one will disappoint you and the Kaizen II will not.
- Concealed tang. Normal for the construction, but a real difference from the full-tang Western-style slicers — including the Misono — that it competes with on price.
- Geometry is unpublished. No spine thickness, no blade height. For a shape where thinness is the entire performance argument, that is the gap we would most like ZWILLING to close, and until it does we are trusting the shape rather than a figure.
How it compares
The Miyabi Koh sujihiki against the two other 240 mm slicers we cover and the Miyabi one step up| | Miyabi Koh | Misono No. 521 | Yoshihiro VG10 | Miyabi Kaizen II |
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| Blade length | 240 mm (published 9.45 in) | 240 mm (245 mm edge per the retailer) | 240 mm | Not made as a 240 mm sujihiki |
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| Steel | FC61 fine-carbide stainless | 13-chrome molybdenum stainless | VG10 core | FC61 fine-carbide stainless |
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| Published hardness | 61 HRC (on the product page) | Not published by Misono (57 HRC is the retailer's figure) | Not published | 60-62 HRC (on the product page) |
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| Published edge angle | 9.5-12° per side, hand-honed | Not published by Misono (70/30 per the retailer) | Not published | 9.5-12° per side, hand-honed |
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| Construction | Mono-steel, mirror-polished, no cladding | Single-layer stainless, made in Seki | VG10 core, 16-layer hammered Damascus | FC61 core, 48 Damascus layers |
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| Published weight | 0.35 lb (about 159 g) | 157 g (retailer's figure) | Not published | — |
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| Handle / tang | Octagonal pakkawood, concealed tang | Pakkawood with steel bolster, full tang per the retailer | Western-style | Pakkawood D-shape, rounded bolster |
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| Really for | A slicer whose spec is written down | Finding out whether you need a slicer | A hand-finished Damascus slicer for less | The same steel with the decoration |
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Against the Misono No. 521 the choice is a documentation argument, not a quality one. Misono has made knives in Seki for a long time and the 521 is a well-regarded working slicer; it is also 157 g of single-layer stainless whose hardness you are taking from a shop rather than the factory, and the retailer’s 57 HRC puts it a meaningful step below 61 in edge retention. It has the full tang and the bolster. If you are not yet sure you need a dedicated slicer, the Misono is the sane way to find out.
Against the Yoshihiro you are choosing a published number over a hammered Damascus face. The VG10 core is a known, good steel — our VG10 guide covers it — but no hardness figure is published for that knife at all, so the comparison is a spec sheet against a photograph. Against the Kaizen II there is no comparison to make at this length: ZWILLING does not sell one. If you want FC61 in a 240 mm slicer, the Koh is the only door. The full field, split by the job you are actually doing, is in the meat-cutting roundup.
Who should buy it
Buy the Miyabi Koh sujihiki if you carve, portion or slice large proteins often enough that a dedicated knife earns its drawer space; if you already own a chef’s knife you are happy with; if you want a hard, acutely ground Seki blade and would rather the money went into the steel than the pattern; and if you are willing to keep it off a honing rod and off bone. The symmetrical octagonal handle makes it one of the easier premium Japanese knives to recommend to a left-hander.
Buy something else if this would be your first good knife; if you want one knife that does everything, in which case a gyuto is the answer; if you are not sure the shape suits how you cook, in which case find out on the cheaper Misono; if you want a knife that looks like the Miyabi photographs you have seen; or if you need visible full-tang construction.
How we reviewed this
We do not own this knife and have not cut with it. This review reads the specification ZWILLING publishes on its own product page for item 33950-243, together with ZWILLING’s own account of the Honbazuke process, its knife use-and-care page and its US warranty terms, against Misono’s own pages for the competing Molybdenum-series sujihiki and the specialist retailer’s spec table for that knife. Where a maker publishes nothing — the spine thickness, the blade height, the composition of FC61, Misono’s hardness — we say so and name whoever does carry the number. Where ZWILLING’s own figures do not sit together — three weights on one site that cannot all be measuring the same thing — we say that too, and decline to build an argument on the ones we cannot trust. Anything nobody states is marked Not published rather than estimated, and no price appears in this text: prices on this site come only from the live daily check and carry the date they were pulled. Our methodology page sets out the whole approach.