Blog
Grit measures abrasiveness: the higher it is, the finer the finish.
1,000 grit is the cornerstone of all sharpening.
To start, a double-sided 1,000/3,000 synthetic stone is enough.
Flatten your stone as soon as it develops a dip.
Choosing a sharpening stone for your Japanese knives means first understanding what grit does to the blade, and what the stone material brings to the experience. At Stay Sharp, this guide presents each grit category, the types of stones, and a clear selection framework according to your steel, your level, and the condition of your blades.
The grit of a sharpening stone is measured according to the JIS standard (Japanese Industrial Standards), the reference for Japanese stones. The lower the number, the larger the abrasive particles and the more material the stone removes. The higher it is, the finer and more precise the work. 240 grit digs and repairs, 1,000 grit sharpens, 6,000 grit polishes. Understanding the scale means knowing what you are doing to your blade with each pass.
Coarse grits, from 120 to 600, are used for one thing: repair. Chipped blade, severely dulled edge, bevel to reform: that is their domain. These are not maintenance stones. On a knife in good condition, a pass on 240 grit would be destructive: you would remove in a few minutes the material that dozens of sessions would have preserved. If your knife still cuts, start directly with the medium grit.
1,000 grit is the absolute reference. It is what performs the sharpening: it recreates the bevel, puts the edge back in place, and prepares the blade for finishing. For the vast majority of home cooks, a good quality 1,000 grit stone is enough for the regular maintenance of all their Japanese knives. If you only have to own one stone, it is that one.
After 1,000 grit, the edge exists but remains rough at the microscopic scale. Fine grits, from 3,000 to 6,000, polish this surface and give the edge its maximum fineness. 8,000 grit and beyond produces a mirror finish, appreciated on hard steels like Aogami or Shirogami, whose structure reveals itself at high granulation. For common household use, 3,000 is enough. 6,000 and more are for conscious refinement.
Modern synthetic stones have a calibrated particle size: each grit is homogeneous and the result is reproducible. It is the logical choice to start and for regular use. Natural stones, coming from deposits like those of certain Japanese quarries, offer an abrasive mud with unique properties, appreciated by enthusiasts. They are less predictable, slower, and often more expensive. For the majority of cooks, a good synthetic stone is suitable in all circumstances.
The diamond stone abrades quickly and wears little: it is suitable for repairing very hard steels or for express maintenance, without soaking. Its disadvantage: often too aggressive for the finishing of fine Japanese blades. The ceramic stone, made of sintered alumina, is conversely slow and precise, without lubricant, ideal for finishing and precision polishing.
For a home cook, a double grit stone, 1,000/3,000 or 1,000/6,000, covers the essentials without multiple investments: one side for sharpening, the other for finishing. Intermediate users benefit from separating the grits: a dedicated 1,000 stone wears more evenly and is easier to flatten. Enthusiasts combine three stones or more for total control. The ideal configuration depends on your sharpening frequency and the desired level of finish.
At Stay Sharp, the sharpening stones offered are those that are used every day on the blades going through the sharpening service. Olivier Caza-Berthelet and his team work on the stone daily: this direct experience guides every reference choice. The stores in Montreal and Quebec City allow you to see and touch the stones before buying. And if the technique still intimidates you, the sharpening service maintains your blades while you learn.
The steel of your knife influences the choice of the finishing grit. Hard carbon steels, like Aogami and Shirogami, with fine crystalline grain, reveal their full potential on high grits, from 3,000 to 8,000. The abrasive mud of these grits plays an active role in polishing. SG2 and VG-10, stainless steels, respond well to a 1,000/3,000 progression, without requiring a finer grit for an excellent result.
With use, every stone eventually develops a dip in the center, where the blade passes most often. A hollow stone no longer allows uniform contact with the edge: the result is irregular, even with good technique. Flattening consists of re-leveling the stone on a flat abrasive surface or on a dedicated stone. It is a five-minute task, to be done as soon as you feel a concavity.
Beginner: a double-sided synthetic stone 1,000/3,000 covers regular sharpening and basic finishing.
Intermediate: two separate stones, a dedicated 1,000 and a 3,000 or 6,000, for more control and more even wear.
Enthusiast: a complete progression 400, 1,000, 3,000, 6,000 or 8,000, with a flattening stone.
The right choice follows your actual sharpening frequency, not your momentary aspirations.
Choosing a sharpening stone for your Japanese knives boils down to three questions: what is the condition of my blades, what is my steel, and what finish am I looking for? Grit answers each one. A quality synthetic stone in 1,000 grit, alone or combined with a 3,000, is enough for the majority of kitchens. The rest is a progression that you will build session after session. See the collection of sharpening stones.
