Kurosaki Sasame COSP Gyuto 240mm

Both are all-purpose Japanese knives, and for most home cooks either will handle the bulk of daily prep. The choice comes down to length, blade shape, and how you like to cut.

A gyuto is the Japanese chef's knife, with a gently curved edge that lets you rock and slide through cuts as well as chop. Tojiro's guide to Western knife shapes gives 150 to 210mm as the household size for a gyuto and up to 360mm for professional use. The extra length and pointed tip give you reach and versatility, from proteins to large produce.

Tojiro's guide to Japanese knife shapes gives 165 to 170mm as the household size for a santoku, which has a flatter profile and a rounded sheep's-foot tip. It rewards a straight up-and-down push cut, feels nimble in smaller hands or tight kitchens, and is the classic Japanese household knife.

Rule of thumb: choose a gyuto if you want one do-everything knife with more reach, or a santoku if you prefer a compact, easy-to-control blade. Plenty of our customers end up owning both.

The gyuto (牛刀) is a chef's knife for all kinds of cooking, and it is basically double-bevel. A knife maker's guide says it came to Japan in the Meiji era with the culture of eating beef, which gave it its name, but it does not cut only meat.

A Japanese dictionary describes the gyuto as slimmer than a santoku, with a pointed tip, used widely for meat, fish and vegetables.

A knife maker's guide lists 150 to 210 mm, double-bevel, for home use, and 180 to 360 mm, single- or double-bevel, for professional kitchens.

We suggest starting with a 210 mm gyuto for a home kitchen, and stepping up to 240 mm if you regularly cut large pieces and have the board for it.

Get the 210mm. We only point people to a 240mm when they have about 45cm of usable board, cook in volume, and regularly break down big roasts or whole fish.

On the gyutos we've measured for our product pages, the extra length is real. As of October 2026, the 210mm gyutos we list have a median edge of 213mm from heel to tip, across the 111 we have measured; the 240mm ones have a median of 240mm, across 100. The 240s are also heavier, 212g against 175g at the median, and a touch taller at the heel, 50mm against 48mm.

That length buys you a longer stroke. A 240 goes through a big piece of meat in one or two pulls and moves a board of chopped vegetables with less shuffling. It costs you board space and control. On a small board the tip hangs off the edge, and fine work like herbs and shallots feels like more knife than the job needs.

Our advice: choose a Japanese knife if you want the keenest edge and do not mind caring for a harder blade, and a German knife if you want a tougher, more forgiving knife you can hone casually and use for heavy prep. On two Japanese knife steels, the steel makers' own figures start at 60 HRC: Takefu Special Steel rates VG10 at 60 HRC or more, and Proterial lists the hardening hardness of Aogami 2 (Blue 2) as over 60 HRC.

Our care advice for a Japanese knife: keep it off bone, frozen food and very hard squash, and use a wooden or plastic board.

The flat spot is the straight run of edge from the heel towards the middle, the part that meets the board along its length. At our counter we call it the sweet spot; elsewhere "sweet spot" often means the balance point, so ask which one someone means.

Past the flat, the edge curves up towards the tip (the belly), which suits a swinging or pulling stroke. Sharpeners also say "flat spot" for a worn patch of edge, so when you mean the shape, "the flat part of the edge" is clearer.

Cobalt Special (CoSP) is Takefu's stainless blade steel for cutlery: Takefu's page describes it as super high-grade and made by a special remelting process that gives a uniform composition and finely dispersed carbides.

Takefu's table gives 1.05% carbon, 16.00% chromium, 1.50% molybdenum, 0.25% vanadium, 0.25% tungsten and 2.50% cobalt, with a hardness of HRC 60 or more. In Takefu's description, tungsten improves tempering resistance, molybdenum adds corrosion resistance, vanadium gives a finer microstructure, and cobalt strengthens the matrix and helps keep a long-lasting edge. Its 16.00% chromium is above the JSSA's 10.5% minimum for stainless, which the JSSA says strictly means rusts less; wash and dry the knife after use.

We think so. Yu Kurosaki established his own workshop in 2014 after twelve years at Kanehiro Uchihamono (カネ弘打刃物), and he was certified as a traditional craftsman (伝統工芸士) in 2019. In a 2022 interview with the magazine Nihonmono, he described his knives as thin, sharp and tough.

We list his knives in steels such as SG2 and Blue Super. For a closer look at his work and approach, you can explore the Yu Kurosaki maker page on the Knives and Stones site.