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Shop for a whetstone and you are hit with numbers right away: 400, 1000, 3000, 6000. Those numbers are grit, and they are the single most important thing to understand before you sharpen a kitchen knife on a stone. Pick the wrong grit and you either waste an afternoon or scratch up a good blade. Here is whetstone grit explained in plain terms, plus which stones a home cook actually needs.
What grit means
A whetstone is an abrasive block. Its surface is made of tiny hard particles that wear away a little steel each time the blade passes over it. The grit number describes how fine those particles are.
The rule is simple. The lower the number, the coarser the stone. The higher the number, the finer the stone. A coarse stone removes steel quickly and leaves a rougher edge. A fine stone removes very little steel and leaves a smoother, more polished edge.
Think of it like sandpaper. You start rough to shape, then move to finer grades to smooth and refine. Knife sharpening works the same way.
Sharpening is not honing
Before choosing a stone, it helps to know when you actually need one. Shun, the Japanese knife maker, draws a clear line between the two jobs.
- Honing realigns an edge that has shifted slightly out of line with normal use. It does not remove steel. A honing steel handles this, and it keeps a knife cutting well between sharpenings.
- Sharpening restores the edge when honing no longer works. It removes a small amount of steel to create a fresh edge, and that is the job of a whetstone.
Shun says that for most home cooks, sharpening its knives once or twice a year is enough. So a whetstone is not an everyday tool. It is the reset button.
Coarse grits: repair and reshaping
The low numbers, like 400, are for a knife that is truly dull. Shun points cooks with an exceptionally dull knife to its 400 and 1000 grit combination stone rather than finer options. Coarse grits work fast, which is what you want when an edge has worn down badly, and what you do not want for routine touch ups, since they remove more steel than necessary.
If your knife still cuts reasonably well, you can usually skip the coarse stone entirely.
Medium grits: the workhorse around 1000
A stone around 1000 grit is where most sharpening happens. Shun describes its 1000 grit side as the one for restoring a dulled edge and putting a keen edge on the knife. If you buy only one grit, this is the one, because it brings an ordinary dull kitchen knife back to sharp without eating away much steel.
Fine grits: polishing at 3000 and up
Fine stones, from a few thousand up to 6000 and beyond, refine and polish the edge left by the medium stone. Shun says its 6000 grit side is for refreshing and polishing the edge after the 1000 side. The result is an edge that glides through food more smoothly.
Fine grits do very little on a dull knife. They are a finishing step, not a fix.
Why combination stones make sense
For most home kitchens, the best buy is a combination stone with a different grit on each side. A 1000 and 6000 stone covers both sharpening and polishing in one block, and it is the setup Shun uses in its Combination Whetstone and in its 3 Piece Sharpening System, which pairs that stone with a honing steel and a bamboo stand set at a fixed 16 degree angle to match the edge on Shun knives. Add a coarse 400 stone later only if you start rescuing badly worn knives.
How to use a whetstone
- Soak or wet the stone. Shun says its combination stone needs a thorough soak before use, and to use it with water only. Always check the instructions that come with your stone.
- Set it on a stable base. The Shun stone includes a rubber tray for stability, and the KING KW65 sits on a plastic base.
- Hold a consistent angle. The angle matters more than speed. Match the angle your knife maker recommends. Shun sharpens its blades to 16 degrees per side.
- Work the medium side first. Sharpen along the whole edge on each side until it feels uniformly sharp.
- Finish on the fine side. Use lighter strokes to refine and polish.
- Rinse, dry and hone. Clean the knife and stone, then use a honing steel between sharpenings to keep the edge in line.
Which grit should you buy
- Your knives are a little dull: a 1000 and 6000 combination stone.
- Your knives are very dull or chipped: add a coarse stone around 400, or ask the maker about sharpening. Shun, for one, offers free lifetime sharpening for its knives.
- You just want to keep a sharp knife sharp: a honing steel, with a stone once or twice a year.
Not sure which knife you are sharpening in the first place? Start with our guide to kitchen knife types, then see the Tojiro DP gyuto, the Global G 2 and the Wüsthof Classic.
For more kitchen and gear picks, browse our buying guides.
