Look for help with a Japanese knife in English and chipping is one of the questions that keeps coming up, in several forms: chipped edge, chip repair, can you use a chipped knife. English knife shops tend to answer it in one of two ways: the steel is hard, so chips are the price of sharpness, or you used it wrong.
Japanese makers and knife shops write about chipping for Japanese customers too, and they are less dramatic about it. A chip is repairable, it is usually caused by something specific, and one cause that almost nobody mentions in English is the sharpener people buy to look after the knife.
The short answer
A chip of a millimetre or so can be ground out at home on a coarse stone, somewhere between 200 and 400 grit, followed by the medium stone you should already own. The part people get wrong is the spot they grind. You do not work on the notch. You take the whole edge down evenly until the notch is gone, otherwise the profile of the knife changes.
A chip you can see from across the room is a job for a sharpener. In Japan that job is cheap. Outside Japan, it costs more, and that difference is the main reason it is worth learning to do the small ones yourself.
What causes it, according to the people who make and sell the knives
Sakai Ichimonji Mitsuhide, a knife shop in Sakai, lists the usual causes in its Japanese maintenance pages: cutting something frozen, fish bones and shellfish shells, twisting the blade while it is in the food, and hitting the board hard as you cut. It adds two that are less obvious. A knife that has been sharpened too thin chips more easily, and so does a knife that has rusted.
On frozen food the shop is blunt. It says frozen food is hard in itself and the chips it causes can be very large, and it asks customers not to use its knives on frozen food at all.
Jikko, another Sakai maker, adds something I had not seen in English. Its repair page says that even without any of those causes, a knife that has gone years without proper sharpening can develop small chips until the edge looks jagged. So a chipped edge is not always a sign that someone did something wrong last week. It can be a sign that nobody has put the knife on a stone for a long time.
Harder steel chips more easily. The makers say so plainly
Tojiro, a large maker in Tsubame-Sanjo, has a page on sharpness and hardness that states the trade-off without any marketing around it. In my translation: the harder the steel, the more brittle it is, which is a matter of course, and a hard, acute edge cuts well but becomes weak against sideways force, so chips happen more easily.
Tojiro puts the sensible range for a kitchen knife at roughly 52 to 62 on the Rockwell C scale. Above that, it says, the blade becomes very peaky, needs care against snapping, and is hard to sharpen on a stone. It also warns that a knife given a very fine final edge is thinner at the tip and more at risk of chipping when pushed sideways.
This is the same trade-off I wrote about in VG10 vs SG2. In that piece a Sakai shop described the harder powder steel as quick to stop cutting once its edge is damaged. If you bought a very hard knife, you bought an edge that stays sharp longer and forgives less.
The sharpener that causes chips
This is the part I think most English guides miss. Tojiro published microscope photographs of the same edge after different treatments: new, dulled, a roller sharpener, a cross-type pull-through sharpener, and whetstones at 1000, 4000 and 6000 grit.
Its conclusion is that a pull-through sharpener does not really sharpen. It roughens the edge so the knife bites into food for a while, and the knife feels sharp again. The roller type leaves the edge serrated like a saw. The cross type leaves sideways scratches and burrs, grinds only the thinnest part of the edge, and makes the edge rounder and worse. Tojiro says that relying only on a sharpener sharply lowers the strength of the edge and can cause cracks and chips. For knives that are made to be sharp, it says the cross type is better not used at all, because it damages the knife.
Tojiro also says that fine scratches from ordinary use make chips more likely, and that in a normal home a knife reaches that dulled, scratched state in about a month. Its advice is a stone once or twice a month, and a sharpener only when you need the knife to cut right now and have no time.
Tojiro sells sharpeners, so this is a maker warning people off one of its own product lines for a certain kind of knife.
How to fix a small chip at home
Jikko published its home method in Japanese, and it is the one I would follow. In summary:
- Start on a coarse stone. Jikko says the usual choice is a stone of roughly 200 to 400 grit.
- Grind the whole edge, not only the chipped part. If you work only on the notch, the shape of the knife changes. Jikko suggests counting strokes, about ten at the heel, ten in the middle and ten at the tip, and repeating.
- Do both sides the same number of times. Do not try to remove the chip from one side in one go.
- When the notch is gone, move to finer stones to clean up the scratches the coarse stone left. Jikko finishes on a 6000 grit stone and flattens every stone before use.
- Put a small secondary bevel on the very edge. Jikko calls this kobatsuke. It gives the edge a little thickness so it chips less easily next time, which matters if the knife was sharpened very thin to begin with.
- Remove the burr by drawing the edge through a rolled-up newspaper.
A coarse stone removes metal quickly. That is the point of it, and also the risk. If this is your first time, practise the stroke on the 1000 grit stone first and only move down to the coarse stone once you can hold an angle.
If you do not own a medium stone yet, I went through which grits a home cook actually needs in what grit whetstone to buy. The short version was a 1000 grit stone and something to keep it flat. A coarse stone was not on that list, and I still would not buy one until you have a chip to fix.
When to send it to someone
English guides draw the line at different sizes. Kasumi Japan, an English-language shop, puts it at 2mm and says professional repair typically costs 20 to 50 dollars.
The Japanese prices are worth seeing, because they show how routine this repair is in Japan. Tojiro publishes its repair fees online. A chip of about 1mm is included in the basic sharpening fee. A chip of 3mm or less adds 330 yen, and a chip larger than 3mm adds 550 yen. The basic fee for a blade of 165 to 180mm, which covers most santoku, is 1,100 yen. So a badly chipped santoku starts at about 1,650 yen to repair, a little over 11 dollars at 150 yen to the dollar. Tojiro calls these figures a guide and gives the final price after it has seen the knife. The turnaround is 7 to 14 business days and the customer pays shipping to Tojiro.
Sakai Ichimonji Mitsuhide prices its sharpening by knife type, for example 1,980 yen for a yanagiba of 180 to 210mm, and says repairs that need chip removal or reshaping cost 50 to 100 percent more.
Neither page says anything about knives sent from abroad, and I would not assume they take them. The practical point is the opposite. For a reader outside Japan, the cheap Japanese repair is not really available, so a local sharpener at the prices Kasumi quotes, or a coarse stone and an hour of your own time, are the realistic options.
Ichimonji says a chip left alone can get worse, and that chips large and small can be put right with proper sharpening.
What I would buy
If you already have a 1000 grit stone and you have a chip: one coarse stone, and nothing else.
Hocho-Knife sells a Sabun 220 grit coarse stone, middle size, at $38.99, which was listed as in stock when I checked on 28 September 2026. It is the cheapest coarse stone I found in the right grit range, and it is the one I would start with.
If you would rather have a thin, hard stone that needs only a splash of water, the Shapton Ha no Kuromaku 320 grit at $49.99 sits in the middle of the 200 to 400 range Jikko gives. Shapton is also the brand of the finishing stone I suggested in the grit article.
Tojiro makes a combination stone with 220 grit on one side and 1000 on the other, sold at Hocho-Knife for $46.99. If you have no stone at all, it covers both jobs in one purchase. Tojiro is one of the brands Hocho-Knife excludes from its programme, so I earn nothing on it and I have not linked it.
Not worth buying for this: any pull-through sharpener, for the reasons Tojiro gives above.
For the wider picture of shape, steel and care, see how to choose a Japanese knife. Rust is one of the causes Ichimonji lists, and I covered telling rust from patina in a separate piece.
Disclosure
I have four approved affiliate partnerships: two with knife retailers, Hocho-Knife and SharpEdge, and two with Japanese language-learning companies unrelated to knives. This page carries two tracked links, both to Hocho-Knife, for the two coarse stones. At about 10 percent, that is roughly 4 dollars and 5 dollars. The option I would pick for someone with no stone at all is the Tojiro combination stone, and it pays me nothing. My full affiliate disclosure is here.
Sources used here, all public and in Japanese unless noted: the Sakai Ichimonji Mitsuhide maintenance pages on chipped knives and its sharpening price list; the Jikko page on repairing chipped knives at home; the Tojiro reading library pages on sharpeners and whetstones and on sharpness and hardness, and the Tojiro repair page; and, in English, the Kasumi Japan guide to chipped knives.