Whetstone Grit Explained: Which Stone Do You Actually Need?
Buying your first whetstone is one of those decisions that looks complicated from the outside and turns out to be much simpler once you understand a few basics. The range of options — from 120 grit all the way to 12,000 — can make it feel like you need to spend a lot and own a lot. You don't.
This guide cuts through the confusion and tells you exactly what you need, based on what you're trying to do.
What Grit Numbers Mean
The grit number refers to the coarseness of the abrasive particles in the stone. Lower numbers = coarser = removes more steel faster. Higher numbers = finer = removes very little steel, refines and polishes the edge.
Think of it like sandpaper for wood. You wouldn't sand a tabletop with 60-grit from start to finish, and you wouldn't try to remove paint with 2000-grit. The same logic applies to sharpening: different grits do different jobs.
For Japanese knives specifically, the grit system also matters more than it does for Western knives. Because Japanese steel is typically harder (often 60+ HRC — see our guide to Japanese knife hardness), finer grits do more work than they would on a softer blade, and the quality of the edge you can achieve at a fine grit is exceptional.
The Three Grit Zones
Coarse (120–400 grit) — Repair and Reprofiling
Coarse stones are for removing significant amounts of steel quickly. You'd reach for one when:
- The knife has a chip or notch in the edge
- The edge has been neglected for a long time and is genuinely dull
- You're changing the bevel angle
- You're thinning behind the edge of a thickening knife
For regular home use, you may rarely or never need a coarse stone if you're maintaining your knives consistently with medium stones. Many home cooks go years without one.
The Morihei Hishiboshi 500 Grit Whetstone is a good coarse option if you do need one — aggressive enough to be useful, but not so coarse that it's hard to control.
Medium (800–2000 grit) — The Workhorse
This is where most of your sharpening actually happens. A medium stone removes enough steel to fully raise a burr and establish a new edge, while leaving a finish refined enough for everyday use.
If you only buy one stone, buy a 1000 grit.
It's the most versatile single stone you can own. A well-executed edge on a 1000 grit stone will be sharp enough to do real work — it just won't have the refined, polished finish of a higher grit.
Two stones we recommend:
Imanishi Arashiyama 1000 — Our most popular entry-level stone. It's fast-cutting, easy to flatten, and forgiving to learn on. An outstanding choice for someone buying their first whetstone. View stone →
Morihei Hishiboshi 1000 — A premium 1000 grit option from one of Japan's most respected stone makers. The feedback and feel are excellent. Worth the upgrade when you're ready for it. View stone →
Fine and Finishing (3000–12,000 grit) — Polishing the Edge
Fine stones don't significantly sharpen a knife — they refine an edge that's already been established on a medium stone. The result is a smoother, more polished bevel that glides through food with less resistance.
At this grit level, a Japanese knife can achieve an edge that feels effortless on delicate ingredients — tomatoes, fish, herbs, soft fruit. The difference between a 1000-grit finish and a 6000-grit finish on the same blade is noticeable, though whether it matters depends on what you're cutting.
6000 grit is where most home cooks who want a refined edge will stop. It produces a very sharp, slightly polished edge without going into full mirror-polish territory.
9000 grit and above takes the edge into near-mirror refinement. This level is appreciated most on single-bevel knives or by cooks who work with very delicate proteins and want the absolute minimum drag through the cut.
Morihei's Hishiboshi series covers both:
Morihei Hishiboshi 6000 Grit →
Morihei Hishiboshi 9000 Grit 'Karasu' →
What Setup Do You Actually Need?
Just starting out
One stone: 1000 grit. The Imanishi Arashiyama 1000 is a great starting point. Learn to sharpen consistently at one grit before worrying about anything else.
Intermediate — want a more refined edge
Two stones: 1000 grit + 6000 grit. This is the setup most serious home cooks settle on. The 1000 does the sharpening work; the 6000 refines the edge to something noticeably finer.
Enthusiast — want the best edge possible
Three stones: 400–500 grit + 1000 grit + 6000–9000 grit. Add a coarse stone for occasional repair work and a high-grit finisher for the best possible edge on premium knives.
Don't Forget: Flatten Your Stones
Whetstones dish over time — they develop a concave hollow in the middle from repeated use. A dished stone makes it much harder to maintain a consistent angle and can actually prevent you from sharpening effectively.
Flattening regularly is one of the most important (and most overlooked) parts of whetstone maintenance. We carry Atoma diamond lapping plates — the standard tool for flattening whetstones. Rub the stone on the diamond plate with water until the surface is flat again. Takes a few minutes and makes a real difference.
A Note on Pull-Through Sharpeners
Pull-through sharpeners — both manual and electric — are not recommended for Japanese knives. They remove too much steel, produce an inconsistent edge, and can damage the finer geometry of Japanese blades. A whetstone takes longer to learn, but the edge it produces and the longevity of the knife make it worth the investment.
If you'd prefer to have your knife professionally sharpened while you're getting started, we offer a knife sharpening service.
Browse all whetstones at Blade & Board → bladeandboard.co.nz/collections/whetstones