Japanese Knife Maintenance: What It Needs, and What Repairs Cost

The question that arrives after the knife does is how much looking after it needs, and what happens if something goes wrong. Most English-language answers to that are technique: hold this angle, use this stone. Fewer of them put numbers on anything, and almost none put a number on what a repair costs.

Those numbers exist. Tojiro, whose knives turn up in most English beginner recommendations, publishes a re-sharpening and repair price list on its Japanese store — by blade length, with a separate surcharge scale for chips. I could not find any of those figures on its English pages.

I live in Japan and read Japanese. Nothing here has been tested by me; it is what makers publish, read in both languages. How this site works.

Whose numbers these are, and what they cover

Everything below comes from one company. Tojiro publishes an unusual amount in Japanese, which is why this page can exist at all, but other makers set their own service terms and prices and I have not surveyed them. Treat the figures as one maker's, not the category's.

It also covers one kind of knife: stainless, double bevel — the gyuto, santoku, nakiri and petty that the shape guide deals with. Single-bevel knives are sharpened differently, carbon steel needs a different rust routine, ceramic needs diamond stones, and serrated edges are their own problem. None of those are in scope here.

What the upkeep actually is

Tojiro's instruction, published in both languages: sharpen once or twice a month. Its Japanese knowledge pages add that how quickly an edge rounds off depends on how the knife is used, and offer roughly a month of ordinary household use as a rough guide.

The daily part is published identically in English and Japanese, so this is a summary rather than a discovery:

• Wash with a soft sponge and neutral detergent, rinse, wipe dry, and store it dry.
• Do not leave it sitting in a sink or a washing-up bowl. Tojiro names both rust and handle rot as the consequence.
• Salt and acid are what start rust, so wash it soon after cutting things like pickles or lemon rather than at the end of the session. Stainless is stain-resistant, not immune.
• If rust does appear: cleanser on a sponge, or take it back to the stone. Not a metal scourer, which scratches.
• Do not dry it in an oven or a microwave.
• On boards, Tojiro's English FAQ says wooden ones are gentler on the edge, while plastic and rubber are easier to keep clean.

That is all Tojiro publishes for routine care. Whether it counts as demanding is a matter of temperament, and mine is in the shape guide.

The stone

Tojiro's English FAQ says whetstones come as rough, medium and finishing, and that a medium stone is sufficient for maintenance at home. It does not say what medium means in grit — though you can work it out from the English product listings, where the stones are named by grit and labelled: #220 coarse, #800 and #1000 medium, #4000 and #8000 fine. So an English-only reader can get to "buy something around #1000" without much trouble.

What that reader cannot get is the reasoning around it. The Japanese pages publish the bands themselves:

The same page offers a combination as a starting point — a #800–1000 as the working stone, with a #400 and a #3000 either side — and is careful to present it as a rough reference gathered from cooks rather than a house standard, noting that the right combination varies by person and by knife. It also warns that jumping more than 3,000 grit points between stones makes the previous stone's scratches difficult to clear, which is the argument against owning only a coarse stone and a very fine one.

The line that applies to a clad blade

One thing on that page I have not found stated in English: for laminated knives, choose the stone for the core steel, not for the cladding. Tojiro's wording is that where a stainless outer layer surrounds a core of carbon steel or something of comparable hardness, you should judge it as sharpening a hard-steel knife. It goes on to match harder and softer stones to different hardness bands.

Following that precisely needs a hardness figure for your particular knife, and makers in this price band do not always publish one. Where it is missing, this refinement is simply not available to you, and no amount of grit selection substitutes for it: how hard a stone is and how fine it is are two different axes. The baseline is unaffected, because it is the grit one — a single medium stone.

The angle, in millimetres as well as degrees

Both language versions give an angle for double-bevel knives. The English one says about 15 degrees. The Japanese one says 10–15 degrees, and adds a figure the English version does not: the gap between the spine and the stone should be roughly 7–10mm. Elsewhere on the same page it describes the angle as about one disposable chopstick.

A height and an angle only correspond for a given blade width, so this is not a universal substitution — it is what Tojiro publishes alongside its own degree figure, for double-bevel knives.

What repairs cost

Tojiro's Japanese store publishes this schedule. The base fee goes by blade length:

Chips are charged on top of that base fee:

Handle work is separate again: from ¥1,320 for a wooden handle, from ¥2,530 for a Western riveted one.

Tojiro describes the whole table as 目安 — a guide. It states that chipping, rust and wear may add work, and that the final price is quoted only after a craftsman has the knife in hand. So the tiers tell you how the company sorts the work and where it charges more; they are not a quote, and they are not a statement about how serious any particular damage is. Checked 28 July 2026.

What using the service involves

• 7 to 14 business days, which is Tojiro's stated turnaround, not a measure of how long the work takes.
• You pay postage both ways. A service voucher, if you have one, covers the return leg and the standard sharpening fee.
• A quote by email after inspection, which you can decline. Return postage on a declined job is yours.
• Serrated blades are not accepted.
• Other makers' knives are not accepted — and are returned freight-collect, which is stated plainly enough to suggest it happens.
• Re-sharpening restores the edge, not the appearance. Tojiro is explicit that stone marks remain, that a damascus pattern fades where the stone touched, and that black coatings come off and cannot be restored. Cosmetic recovery is a separate paid service.
• Packing: wrap the blade in newspaper or card and tape it so the edge cannot work its way out. Tojiro also recommends keeping the box and sheath a knife arrives in, because they make sending it away straightforward.

If you are not in Japan

The intake for all of the above is a Japanese-language form, with payment through a Japanese online shop and postage in both directions. Whether knives are accepted from outside Japan is not something I could confirm either way, so do not plan around it.

The wider question — sending a knife out of your country for repair and bringing it back — is not something this site has looked into, and I would rather say so than wave at it. How to buy from Japan covers importing a purchase, and the warranty and returns problems that come with buying from a domestic Japanese seller. It does not cover a repair round trip.

What the schedule above is useful for, wherever you live, is knowing how a maker sorts this work before you hand your knife to somebody local: an edge restoration, a chip, and a change of shape are three different jobs.

What puts a chip in one

Tojiro publishes this in English as well as Japanese: chips mostly come from hard ingredients, frozen food and bone, and from twisting the blade sideways when it stalls mid-cut. Its instruction there is to pull the knife straight back out and start the cut again rather than levering it free. It also notes that sharpening a blade progressively thinner raises sharpness and lowers strength.

Its English FAQ adds a point worth passing on: a chipped fragment in food is a hazard, which is a reason to look at the edge after you hit something hard rather than after the meal.

Whether a kitchen that does those things should be buying this category at all is a question for before the purchase, and the shape guide settles it there.

Which of these you are in

It has just gone dull. That is the ordinary state, and it is what the once-or-twice-a-month instruction is for. One medium stone.

There is a nick you can feel with a fingernail. On Tojiro's schedule a chip of about a millimetre adds nothing to the base re-sharpening fee. Worth knowing before you decide the knife is ruined, and worth asking a local sharpener how they price it.

It is bigger than about 3mm, or the tip is gone. The maker charges more for the first and quotes case by case for the second. Both are still repairs.

The handle is loose. Compare the replacement figures above against the price of the knife before deciding which one you are doing.

→ If you have not bought one yet, the shape decision comes first: which Japanese knife do you actually need.