The Correct Japanese Knife Sharpening Angle (Santoku Included)

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Updated September 2026 · 8 min read · UK Japanese knife specialists

The sharpening angle is simply how far you tilt the blade away from the stone. Tilt it less and you get a thinner, keener edge that slices beautifully but is more fragile. Tilt it more and you get a stubbier, tougher edge that survives abuse but never feels truly sharp. Japanese-steel knives sit deliberately at the keen end of that trade-off, which is why they cut the way they do — and why the angle you sharpen them at actually matters.

This guide gives you the number for your knife, three ways to find it if you are not sure, and the one trick that turns “roughly 15°” into a repeatable edge. If you would rather start with the basic motion first, our step-by-step whetstone guide covers the strokes themselves.

What “15 degrees” actually means

This is where most confusion starts, so it is worth being precise. Lay the knife flat on the stone and the angle is 0°. Stand it straight up and it is 90°. The sharpening angle is measured per side — from the face of the stone to the face of the blade.

Nearly every Japanese knife sold for Western kitchens, including everything we stock, is double bevel: it is ground symmetrically on both faces to form a V. So a knife sharpened at 15° per side has a 30° inclusive edge. Manufacturers quote it both ways, which is exactly why you see “15 degrees” and “30 degrees” used for the same knife. They are the same edge described from two directions.

The exception is the traditional single bevel knife — a yanagiba, an usuba, a classic deba. One face carries the whole bevel and the other is flat (in fact slightly concave). You only sharpen the bevel side, so 15° on that face is the entire edge, and the result is dramatically thinner than any double-bevel knife. If you own one of these, see our guide to single bevel vs double bevel knives before you touch it to a stone.

For comparison, a typical German or other Western chef's knife is ground at roughly 20° per side, a 40° inclusive edge. That is the practical difference you feel when a Japanese-steel blade drops through a tomato that a Western knife wants to squash.

Knife sharpening angle chart

These are the working angles we would use on each blade type. Treat them as a starting point rather than gospel — a degree either way is not going to spoil an edge.

Knife	Per side	Inclusive edge	Why
Santoku	14–15°	28–30°	Flat edge doing fine vegetable work — keep it keen
Gyuto / chef knife	15°	30°	The all-rounder standard — sharp but robust enough
Nakiri	14–15°	28–30°	Vegetables only, never bone — can run thin
Petty / paring	14–15°	28–30°	Detail work rewards a fine edge
Boning	16–17°	32–34°	Meets bone and joints — a little more shoulder helps
Single-bevel (yanagiba, usuba)	10–15° (bevel face only)	10–15°	One face carries the whole edge
Western / German chef knife	20°	40°	Softer steel, built for durability over keenness

Serrated bread knives are the exception — you do not sharpen them at a set angle. See how to sharpen a serrated knife.

How to find the angle on your own knife

1. Check the maker first. If you know the model, the manufacturer usually publishes the factory grind. Ours are ground at approximately 15° per side, so 15° is the number to match. Matching the factory angle is the fastest route to a sharp knife, because you are refreshing the existing bevel rather than cutting a new one.

2. Follow the bevel by feel. Lay the blade flat on the stone, then lift the spine slowly until the existing bevel sits flush against the surface. You will feel it settle. That is your factory angle, and it is a more reliable read than any measurement — a protractor struggles on a worn edge because the very apex is rounded over.

3. Use the marker trick to check. Colour the bevel with a permanent marker, make two or three light passes, then look. Ink gone from the whole bevel means your angle matches. Ink left at the very edge means you are too low; ink left up near the shoulder means you are too high. It takes ten seconds and removes all the guesswork.

If you cannot establish an angle any other way, default to 15° and commit to it. A consistent 15° edge will always outperform a wandering “perfect” one.

Holding the angle steadily (the part that actually matters)

Almost nobody can hold 15° freehand from heel to tip on their first go. The good news is you do not have to. There are two reliable shortcuts.

The coin trick. Stack coins under the spine of the blade to set the height, and the angle takes care of itself. The stack you need depends on how wide the blade is, so this is geometry rather than a fixed number of coins: for roughly 15°, the spine needs to sit about a quarter of the blade's width above the stone. On a typical 45 mm-tall santoku that is around 12 mm of coins. Measure once, note the stack, and reuse it every time.

An angle guide. Simpler still — a clip that sits on the spine and rides along the stone, keeping the blade at a fixed angle for the whole stroke. It removes the single biggest source of error for beginners, and it is the reason a first attempt with a guide usually beats a tenth attempt without one. Our angle guide walkthrough shows it in use.

What to sharpen on

A whetstone is the right tool for a Japanese-steel knife, and it is the only method that gives you real control over the angle. Pull-through sharpeners and most electric machines impose their own fixed angle — usually a Western 20° — which quietly grinds away the thin geometry you paid for. We go into that in can you use an electric sharpener on a Japanese knife.

Grit does the other half of the job. Coarse stones (around 400) reset a damaged or genuinely blunt edge. A 1000 grit stone is the workhorse that puts a proper cutting edge back on. Anything from 3000 upwards refines and polishes that edge to the glassy finish Japanese knives are known for. For most home cooks, 1000 then 3000 is all you will ever need; the coarse side is for rescue jobs. Our whetstone grit guide goes deeper.

Honing and sharpening are not the same job, and mixing them up is the most common reason a knife feels dull sooner than it should. A steel pushes a rolled edge back into line; a stone removes metal and creates a new one. Most weeks you want the steel. Every few months you want the stone. Our whetstone vs honing steel guide sets out when to reach for which.

15° vs 20°: which should you use?

The honest answer for a Japanese-steel knife is 15°, and the reason is the steel itself. VG10 and AUS-10 are hardened to a level that supports a thin edge without folding over. Grinding one of them to 20° does not make it tougher in any useful way — it just makes it cut worse while removing a lot of metal to get there.

20° per side belongs to softer Western steel, where a thin edge would roll under normal use. If you own both kinds of knife, sharpen them differently rather than settling on one compromise angle for the drawer.

There is one sensible exception: if a particular knife keeps chipping — usually because it is meeting bone, frozen food or a hard board — nudging it out to 17° adds a little support behind the edge. Fixing the habit is usually the better answer. Our guide to chips in a blade covers the usual causes.

Water, oil or dry?

This is decided by the stone you own, not by preference — and it is worth getting right, because using the wrong lubricant can permanently clog a stone.

Water stones — including ours, and the overwhelming majority of Japanese stones — are used with water and only water. Soak the stone until bubbles stop rising, usually five to ten minutes, then keep the surface wet as you work. The slurry that builds up is doing useful cutting, so do not rinse it away mid-session.

Oil stones are a different product — typically Arkansas or India stones — designed to be used with honing oil. Never put oil on a water stone: it soaks into the pores, the stone stops cutting, and there is no reliable way back. If you are unsure which you have, our guide on telling an oil stone from a water stone will settle it in a minute.

Dry is best avoided on either. Without lubrication the swarf has nowhere to go, the surface glazes over, and friction heat is not doing your edge any favours. Splash-and-go stones exist that need only a wetted surface rather than a full soak, but “dry” and “sharpening stone” do not really belong in the same sentence.

A few things that quietly ruin the angle

Leaning harder as you tire. Pressure changes the effective angle and rounds the apex — light, even strokes beat heavy ones every time.

Lifting the handle to reach the tip. As the blade curves upward towards the point, the contact patch moves; raise the handle slightly and swing, rather than tilting the whole knife.

Working on a dished stone. A stone that has worn hollow in the middle changes your angle without telling you. Flatten it periodically — see how to flatten a whetstone.

Stopping before you have raised a burr. If you cannot feel a faint wire edge along the far side, the two bevels have not met yet and the knife will not be sharp no matter how tidy the angle was. More on the usual mistakes in things to avoid when sharpening knives.

Frequently asked questions

What angle should I sharpen a Japanese knife at?

About 15 degrees per side on a standard double-bevel Japanese knife, which gives a 30 degree inclusive edge. Traditional single-bevel knives are ground on one face only, at roughly 10 to 15 degrees.

What is the correct santoku knife sharpening angle?

Around 14 to 15 degrees per side, so 28 to 30 degrees in total. A santoku spends most of its life on vegetables, so it rewards the keener end of the range rather than a tougher, wider edge.

Is 15 degrees or 20 degrees better for a kitchen knife?

It depends on the steel. Hard Japanese steel such as VG10 supports 15 degrees per side and cuts noticeably better for it. Softer Western steel is usually ground at 20 degrees because a thinner edge would roll in normal use.

How do I know if my knife is 15 or 20 degrees?

Colour the bevel with a permanent marker and make two or three light passes on a stone at the angle you think is right. If all the ink comes off the bevel you have matched it. Ink left at the very edge means you are too shallow; ink left near the shoulder means you are too steep.

Do I need an angle guide, or will coins do?

Both work. Coins set the spine height and cost nothing, but the stack you need depends on how tall your blade is, so you have to measure it once. A clip-on angle guide holds the same angle from heel to tip without any measuring, which is why beginners get sharper results with one.

Is a 1000 grit whetstone enough?

Yes for everyday sharpening. A 1000 grit stone puts a genuinely sharp working edge on a kitchen knife. Finishing on 3000 or higher refines and polishes it further, and a coarser stone around 400 is only needed to repair damage.

How often should I sharpen my Japanese knife?

For most home cooks, every few months on a stone is plenty, with a honing steel used far more often to keep the edge aligned in between. Cook daily and you will want the stone more like monthly.

Do you push or pull when sharpening a knife?

Either is fine as long as the angle and pressure stay constant. Edge-leading strokes give many people better control and a cleaner apex, but consistency matters far more than direction.

Can I sharpen a bread knife at 15 degrees?

No. A serrated blade is not sharpened at a set angle across the whole edge. Each scallop is worked individually with a tapered rod, and only the bevelled side is touched.

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