Whetstone Basics: What a Whetstone Is and How to Use One

Updated August 2026 · 8 min read · UK Japanese-steel knife specialists

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A blunt knife is the most dangerous thing in a kitchen. It skids off the skin of a tomato instead of biting into it, and when it finally does slip, it slips towards your hand with all your weight behind it.

A whetstone is the tool that fixes that properly. It is not the fastest option and it is not the easiest, but it is the only one that gives you full control over the edge — which matters enormously on a hard Japanese-steel knife, where a pull-through sharpener can do real damage. Here is everything you need to know before you start.

What a whetstone actually is

A whetstone — also called a water stone or sharpening stone — is a flat block of bonded abrasive. Dragging the blade across it removes a controlled amount of steel and grinds two new bevels that meet in a fresh, keen edge.

Most stones sold today are synthetic, usually aluminium oxide or silicon carbide bonded in a resin or ceramic matrix. Synthetics won because they are consistent: every stone of a given grit cuts at the same rate, which natural stone never quite managed. Japan's famous natural finishing stones from the Kyoto region were largely worked out and commercial quarrying had all but ended by the late 1960s; today they are a collector's item rather than a working tool.

The number printed on a stone is its grit — the size of the abrasive particles, exactly as on sandpaper. Low numbers are coarse and cut fast; high numbers are fine and polish. Most kitchen stones are double-sided, with a coarser and a finer face.

Which grits do you actually need?

Grit	What it's for	How often you'll use it
200–600	Repair — chips, badly rolled edges, reprofiling	Rarely, and only when something's gone wrong
1000 — the essential one	Actual sharpening: raises a burr and creates the edge	Every time you sharpen
3000–6000	Refining and polishing — smooths the edge, improves glide	Every time, straight after the 1000
8000+	Mirror finishing for very hard steel and fine slicing work	Optional — a genuine improvement on hard VG10, not essential

If you buy one thing, buy a 1000/3000 or 1000/6000 combination stone. The coarse repair grits are worth having eventually, but you should not need them on a knife that is looked after. Our fuller breakdown of what grade of whetstone to buy goes grit by grit.

Soaking: how long, and when not to

This trips up more beginners than the sharpening itself, and the rule depends on the grit.

Coarse and medium stones (up to about 1000–2000 grit) are porous. Submerge them in water for around 5–10 minutes, until the stream of bubbles stops. A dry medium stone clogs with steel swarf and stops cutting.

Fine stones (3000 grit and above) should not be soaked. They are denser, they absorb very little, and prolonged soaking can soften the binder and cause cracking. Splash water on the surface as you work and top it up — this is what "splash-and-go" means.

Never leave any stone soaking indefinitely, and never store one wet. More detail in our guides on how long to soak a whetstone and telling an oil stone from a water stone — putting water on an oil stone, or oil on a water stone, ruins it.

Your first sharpen, step by step

Set the stone on a damp cloth or its non-slip base so it cannot move. Allow 10–15 minutes for a routine touch-up on a well-kept knife; a neglected edge that needs the coarse side first may take 30–40 minutes the first time.

1. Set the angle. Lay the blade on the 1000-grit face at about 15° for a Japanese double-bevel knife — roughly two stacked £1 coins under the spine. Western knives take a wider 20°. The correct sharpening angle matters more than anything else here; a plastic angle guide clipped to the spine makes it repeatable while you learn.

2. Work the first side. Two fingers on the flat of the blade near the edge, light pressure, and push the blade away from you along the stone. Work in sections — heel, middle, tip — counting your strokes so you can match them on the other side. Keep the stone wet.

3. Feel for the burr. After 10–20 strokes per section, run a fingertip carefully across (never along) the opposite side of the edge. A tiny wire lip means you have ground all the way to the edge — that is the signal to switch sides, and the single most useful thing to learn. Our guide to feeling for a burr explains what you are looking for.

4. Repeat on the second side with the same angle and roughly the same stroke count, until the burr flips to the first side.

5. Refine. Rinse the knife and the stone, flip to the 3000 or 6000 face, and repeat with much lighter pressure and far fewer strokes. This removes the burr and leaves a smooth, durable edge.

6. Test it. A sharp knife falls through a ripe tomato under its own weight, and slices cleanly through a sheet of paper held in the air. If it tears or skates, go back to the 1000 and chase the burr again — almost every failed sharpen is a burr that was never fully raised. For a fuller walkthrough with photos, see how to sharpen a knife using a whetstone.

Looking after the stone

Water only. Never put oil, grease or washing-up liquid on a water stone — it clogs the abrasive permanently.

Keep it flat. Stones wear into a dish in the middle, and a dished stone rounds your edge instead of sharpening it. Check it against a straight edge every few sessions and flatten it when needed — see how to flatten a whetstone.

Rinse and dry. Wash the metal swarf off after use and let the stone air-dry completely before it goes back in its box, or you will find mould on it.

Don't freeze it. A soaked stone left somewhere cold enough to freeze will crack as the water expands. Keep it indoors.

Whetstone vs the alternatives

Honing steel. Not a sharpener at all — it pushes a rolled edge back into line. Use one weekly between sharpenings; it does not remove enough steel to create a new edge. See whetstone vs honing steel.

Pull-through sharpeners. Fast, cheap, and they tear a coarse, fragile edge at a fixed angle that is usually far too wide for a Japanese knife. They also take off a lot of steel each pass.

Electric sharpeners. Convenient for soft Western knives. On a hard, thin Japanese-steel blade they can overheat the edge and grind away far more than necessary — we cover the risks in can you use an electric sharpener on a Japanese knife.

Which stone to buy

Frequently asked questions

What is a whetstone and why is it called that?

A whetstone is a flat block of bonded abrasive used to grind a new edge onto a knife. The name comes from the old English verb "to whet", meaning to sharpen, and has nothing to do with the stone being wet — although most modern kitchen stones are water stones and are used wet.

What grit whetstone do I need for kitchen knives?

A 1000-grit face does the actual sharpening and a 3000 to 6000-grit face refines and polishes the edge. That pair handles all normal kitchen sharpening. Coarse grits below 600 are for repairing chips, and 8000 and above is optional polishing that a hard steel such as VG10 will genuinely benefit from but does not require.

How long should I soak a whetstone?

Soak coarse and medium stones up to about 1000 to 2000 grit for roughly 5 to 10 minutes, until the bubbles stop rising. Do not soak fine stones of 3000 grit and above; splash water onto the surface as you work instead. Prolonged soaking can soften the binder in a fine stone and cause it to crack.

How long does it take to sharpen a knife on a whetstone?

A routine touch-up on a well-maintained knife takes about 10 to 15 minutes across both grits. A neglected or damaged edge that needs coarse-grit work first can take 30 to 40 minutes the first time. Once the edge is restored, regular short sessions keep it there.

What angle should I hold the knife at?

Around 15 degrees per side for a Japanese double-bevel knife, which is roughly the height of two stacked £1 coins under the spine. Western knives are usually sharpened at about 20 degrees. Holding a consistent angle matters far more than hitting an exact number, so use the angle guide while you learn.

Can I use oil on a water stone?

No. Oil clogs the abrasive in a water stone permanently and the stone will stop cutting. Use clean water only, and never washing-up liquid or grease. Oil stones are a different type of stone entirely and should only ever be used with honing oil.

How often should I sharpen on a stone?

For a home cook, roughly every two to six months depending on how much you cook and what you cut. Use a honing steel weekly in between to keep the edge aligned. The real test is the knife itself: if it will no longer bite cleanly into a tomato skin, it is time for the stone.

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