The grit number on a Japanese whetstone is not a measurement you can compare across makers. There is no dominant standard behind it.
The four standards, side by side: what #1000 means under each →
Own something else Japanese? Check what will destroy it →
Wikipedia’s article on sharpening stones states the problem plainly: there is no dominant standard for the relationship between grit size and particle diameter. Part of the reason is that “grit size” is used to describe the smoothness of the finish a stone produces, not only how large its particles are. The finish also depends on the shape of the abrasive particles, how much of each is exposed by the binder, whether they fracture into smaller ones under pressure, their hardness, and what they are made of.
So two stones stamped with the same number can cut differently, and a number from one maker does not transfer to another. What does transfer is the rough progression: around 200 for reshaping a damaged edge, around 500 for producing a sharp one, 1000–2000 for an edge finer than most factory edges, and 4000 and up for polishing. Those are the figures the same article gives, and they are the level of precision the number can actually support.
Natural Japanese stones are a separate case again: they are classed as ara-to (rough), naka-to (medium) and shiage-to (finishing), and converting those classes to a grit number is difficult because the classes are broad and a natural stone has no inherent grit number at all. A natural stone sold with a number attached has been assigned one by somebody.
Japanese whetstones on Amazon — the shelf ↗
For a single-bevel Japanese knife the usual starting pair is a 1000-grit stone to sharpen and a 3000-grit to polish; Japanese Knife Lab recommends exactly that pair from the start for yanagiba, with 6000 and above as an optional mirror finish. Buy the pair rather than one stone: a fine stone alone cannot restore an edge, and a coarse stone alone leaves it rough.
Read the number as a band rather than a figure, and compare stones within one maker rather than across makers. If a listing gives a grit number and nothing else — no maker, no indication of whether the stone is synthetic or natural, no statement of what it is for — it has told you less than it appears to. The pairing matters more than the precision: a stone to sharpen and a stone to finish.
Japanese whetstones on Amazon — the shelf ↗
That is the shelf, not a pick. The honest version of the advice above is “buy a 1000 and a 3000 from the same maker”, and which maker is exactly the judgement this site cannot make without owning and using the stones — so what is linked is the search, and the checking is yours. The knife guide it follows from is linked below.
SourcesThe scent exists because the tree was infected. Uninfected wood is pale and light — whatever was added.
Glass dents, rolls and chips edges rapidly. Wood is self-healing — but grain matters more than "hardwood".
Two of these are the same knife. And a nakiri suits either hand; the usuba it resembles does not.
JIS defines it — and the definition says most washi today is machine-made from chemical pulp.
Carved from a single piece, so a snapped tine is not a repair. The tine count is a spec, not a score.
Not a quality ladder. Natural hair holds powder; synthetic is built for cream and liquid.
ISO and Japanese labelling define how matcha is made. Neither defines a grade.
Ground on one side only. The wrong side does not cut badly — it does not work.
Blue holds an edge longer and is harder to sharpen. Which is better depends on how often you sharpen.
One protects the blade, the other eats it. Scrubbing the wrong one leaves the knife worse off.
Western knives sit at 52–58 and 20–22°; harder steel is what permits 15–18°. Higher is a different bargain.
Repair is subtraction — grind past the chip on a coarse stone, then work back up the grits.
A gifted knife is said to sever the relationship. The custom is that the recipient hands back a coin.
Friction-fitted, not bonded — so it can be replaced. And a D-shaped handle is made for one hand.
The usual fix starts by soaking it. A seiro maker calls soaking strictly forbidden.
Dishwasher, microwave, sunlight. All normal, all irreversible on urushi.
Uncured urushi gives most people a rash. Cured, reactions are possible but less common.
A prefectural institute put eleven lacquer films through JIS Z 2801. Most came back undetectable.
The original ceased production around 1900. Since 1973 the word has meant pattern welding — decoration.
It conducts heat badly. That is the product — and it is also why it cracks.
Unglazed clay is porous until rice starch seals it — one simmer, once.
Induction heats metal, not clay. Most donabe never get warm — and cannot be converted.
Real urushi cures in a humid box over days to weeks. A kit that sets in an hour is something else.
Not urushi against epoxy. Whether the material states food-contact compliance.
Pointed where Chinese ones are blunt. And two ordinary gestures read as funeral rites.
Sumi is soot held by animal glue. India ink needs no binder and dries waterproof on its own.
The body is impermeable. It is the decoration that is exposed — and you can feel which kind it is.
One boils water and gives you iron. Putting the other on heat cracks its lining for good.
The spots appear in the first week. The makers’ association says do not take them off.
The form is settled by a 2003 paper. The amount is not settled by anything.
