Oroshigane: How to Choose a Japanese Grater, and Why the Teeth Matter More Than the Metal

Two Japanese kitchen sites, two sets of instructions, and they read almost identically: go slowly, move in circles, don’t lean on it. One of them is teaching you to make wasabi as hot and as fragrant as it will ever get. The other is teaching you to make grated daikon mild enough that a child will eat it.

Both are right. What decides which result you get is not your hand — it is the surface under it. A Japanese grater, an oroshigane (おろし金), is a field of teeth, and the height, the spacing and above all the irregularity of those teeth decide how many cells of the vegetable get opened. Everything else on the product page follows from that: copper or porcelain or sharkskin or bamboo, the well that catches the juice, the price, and whether the maker will ever repair it.

So read the teeth. The metal is mostly a proxy for them.

Grating is not one job

Fresh wasabi has almost no smell until you destroy it. The aroma and the heat appear when the cell walls rupture and the contents meet air, which is why every Japanese wasabi grower gives the same instruction: hold the rhizome upright against the grater and turn it in slow circles, without pressing. The circular motion works air into the paste, and the finer the surface, the more cells you break — more fragrance, more heat, a paste that turns creamy rather than gritty.

Daikon carries the same family of compounds and needs no encouragement. The Japanese advice for a gentle daikon oroshi is, word for word, almost the same: slow, circular, light pressure. Lean on it and saw back and forth instead, and you rupture far more cells and the pile turns sharp.

One instruction, two opposite goals. That is the reason Japan never settled on a single grater. It kept four surfaces, each of which fails at the others’ job on purpose.

What the teeth actually do

Here are the five surfaces you will actually meet when shopping, drawn at the same magnification. Look at the profiles before you look at the material names.

Nothing about the metal makes the grate. Copper is simply the material a person can raise a tooth on by hand, and porcelain is hard enough to keep an edge once it has been set into a softer body. Both are means to a tooth. This is the same bargain as the suribachi, where the hand-carved comb grooves do the grinding and the wooden pestle only presses food into them: in a Japanese kitchen the tool’s surface tends to do the work, and the arm supplies direction.

The copper grater, and what its teeth cost

Copper graters are made by honmedate (本目立て) — a craftsman raising the teeth one at a time with a chisel and a hammer on a tin-plated sheet of hardened pure copper. The shape is old: the hagoita, the flat paddle with a handle, is drawn in the Wakan Sansai Zue, the illustrated encyclopaedia Terajima Ryōan finished in 1712, in essentially the form sold today.

Ōya Seisakusho, the best-known maker still doing it, describes the result of the handwork plainly on its own site: the spacing and the height of the teeth come out subtly uneven. That is not a tolerance being apologised for. It is the feature. Because no two teeth stand at the same height, a fresh set of edges meets the daikon on every stroke, so you don’t have to keep rotating the radish and you can work with a light hand — which, as we have just seen, is also what keeps it mild.

Their double-sided paddles run from No.1 down to No.6. From the maker’s own price list in August 2026:

Size	Dimensions	Weight	Price (incl. tax)	Who it is for
No.1	30.0 × 18.5 cm	725 g	¥21,230	Restaurant service
No.3	24.5 × 15.0 cm	404 g	¥14,960	Large households, big daikon
No.4	22.5 × 13.0 cm	320 g	¥10,450	The default household size
No.6	19.0 × 10.5 cm	244 g	¥8,140	Small kitchens, two people
Yakumi (hagoita)	9.2 × 5.8 cm	51 g	¥2,530	Ginger, garlic, wasabi only

Now the number that settles the argument of this article. When the teeth eventually wear down, Ōya will grind the old ones off and cut new ones, and the charge for that service is half the list price of a new grater of the same size — ¥4,750 plus tax on a No.4 that lists at ¥9,500 before tax. About three weeks, there and back.

Read that as the maker pricing its own product for you. Half of what you handed over was the teeth. The copper — the part every product description leads with — is the other half, and the copper never wears out.

Two useful details from the same source. The maker says to send it in when the daikon starts to slip, not on a schedule: years of use and a discoloured surface are not by themselves a reason to repair anything. And the cleaning instruction is a toothbrush with ordinary washing-up liquid on the copper, a sponge on the tray and drain screen, then a rinse. What is not said, but matters more than any of it: a copper grater has to be dried the moment you finish. If your kitchen is one where things sit in the sink until morning, this is the wrong tool and no amount of craftsmanship will fix that.

The ceramic ginger grater most kitchens should buy first

The good Japanese ceramic graters are not moulded in one piece. Sharp porcelain fragments are set into an earthenware body — hard, angular, irregular chips embedded in a softer clay, which is why they cut rather than mash. Motoshige, in the Iwami district of Shimane, has been making cooking ceramics since 1925 and makes these alongside its suribachi; it is the same idea as that bowl’s carved grooves, executed in a different way. If the words earthenware and porcelain in one sentence seem odd, our guide to Japanese pottery styles explains why the two behave so differently.

The plate form comes in roughly Ø 10.5 cm (23 mm deep), Ø 15 cm (27 mm) and Ø 19 cm (40 mm). The depth is the part people overlook: it is a well, and it catches the juice. For ginger that juice is the ingredient — it goes into the dressing, the ponzu, the pork marinade — and a flat paddle grater throws it at the chopping board.

The trade-offs are real and worth stating. A porcelain chip is blunter than a hand-cut copper hook, so you press harder, which for daikon means a wetter, sharper result. Fibres tangle less than on stamped metal, and the surface does not rust or hold onto the smell of garlic. It also breaks if you drop it, which stamped steel does not. For whether it can go in the dishwasher, see our guide to what Japanese ceramics can and cannot survive — the answer depends on the piece, and the maker’s instruction wins.

One warning. The cheap all-in-one ceramic discs with rounded bumps — the sort sold as a “ginger plate” in every homeware shop — are a different tool wearing the same name. Blunt bumps crush. They are pleasant for garlic and passable for ginger and they will make a watery mess of daikon.

Sharkskin: the wasabi grater, and whether you need one

A samegawa oroshi is a piece of real shark skin, applied by hand to a board of Japanese hinoki cypress. The small ones are around 5 × 9 cm and 1.2 cm thick, with a skin panel of about 5 × 4.5 cm, and start near ¥3,300. The skin is a dense field of tiny denticles, finer than anything a chisel can raise, and it turns a wasabi rhizome into a pale, sticky cream instead of a wet crumb.

The technique is the one described at the top of this page: hold the rhizome upright against the skin and turn it in unhurried circles without pressing. Grate what you will eat in the next few minutes and no more.

The care rules are what decide it for most households. Rinse it quickly, dry it in the shade, never leave it sitting in water and never put it in the sun or a dishwasher — the skin lifts off the wood. This is a wooden implement with a glued skin, closer in temperament to a cedar bento box or a piece of lacquerware than to anything metal.

So the honest answer: if you buy fresh wasabi, buy one, because the tool genuinely changes the result. If you use the tube, no grater on earth will improve it, and a beautiful hinoki board will spend its life in a drawer.

Oni-oroshi: the grater that misses on purpose

The oni-oroshi — “demon grater” — is bamboo, with big teeth set far apart, and it exists to do the opposite of everything above. Because the teeth are coarse and widely spaced, most of the daikon’s cells are never opened. Less water is released, less pungency develops, and what lands in the bowl is a fluffy, crunchy shred rather than a slush.

Bamboo is the material for a reason its makers give directly: it is very hard, and it conducts heat poorly, so it does not warm the vegetable as you work. A typical carbonised-bamboo one measures about 20 × 8.5 cm across the head, roughly 30 cm including the handle, weighs about 110 g and costs ¥2,420. Two working notes from the maker: wet it before use so the teeth tighten up, and pull the vegetable toward you in one direction rather than circling. Rinse it quickly, wipe it, let it dry in open air, and never store it in a plastic bag — that is how bamboo goes mouldy.

Use it for mizore nabe, for ponzu, for a mound of daikon beside grilled fish, and for the dipping sauce you drink out of a soba choko — anywhere the grated daikon has to keep its texture in liquid rather than dissolve into it. It is also the one to reach for when you are serving cold soba or udon.

How hard you press is a seasoning decision

Once you own a grater, four things — none of which cost anything — control how hot the result is. Japanese cooks treat them as seasoning, the way you would treat salt.

The first dial is the one most people have never been told about. Pungency is not evenly distributed through a daikon: it builds toward the tail, and Japanese growers put the tip at as much as ten times the concentration found near the leaves. If a household member complains that grated daikon is too sharp, you do not need a different grater — you need the top 15 cm of the radish.

The fourth dial catches people out in the other direction. The compound responsible is volatile, so a bowl of grated daikon that was fierce when you made it will be tame twenty minutes later. If you want the bite, grate it last, after the fish is off the grill.

The numbers on the box, and what they don’t mean

Ōya’s paddles are numbered No.1 to No.6, largest to smallest. Nothing obliges any other maker to use the same scale, and this is exactly the trap that gō (号) sets on donabe, where an “8-gō” pot from two makers can be two different pots. Our guide to reading a Japanese listing takes that apart in detail, and the sizes and terms reference has the conversions. The rule is simple: ignore the number, buy the centimetres.

As a starting point: for daikon you want a working surface you can actually travel across, which is why the 22.5 cm No.4 is the default household size in Japan; and the 9 cm condiment paddle is not a small daikon grater, it is a ginger, garlic and wasabi tool, full stop. If the listing gives you a number and no centimetres, that silence is the answer — the same silence the rest of the Japanese tableware world keeps about microwaves.

Care, by material

Surface	After use	Never
Tin-plated copper	Washing-up liquid and a toothbrush along the teeth; rinse; dry at once	Leave it wet. Discolouration of the tin is expected and the maker says it is not a fault
Porcelain in earthenware	Brush out the fibres; wash as you would any ceramic	Assume it survives a fall or a dishwasher
Sharkskin on hinoki	Quick rinse; dry in the shade	Soak it, sun-dry it, or put it in a dishwasher — the skin lifts
Bamboo	Quick rinse; wipe; dry in open air	Store it in a plastic bag; that is how it goes mouldy

The general rules for the ceramic side — soaking, staining, drying, storage — are in our guide to caring for Japanese ceramics, and the microwave and dishwasher question is answered piece by piece in this guide. Where a maker’s instruction differs from any of it, follow the maker.

If you are buying one, buy this one

A Ø 15 cm ceramic plate with porcelain chips set into it, for the price of two bowls of ramen. It grates the three things a home kitchen actually grates, it keeps the juice, and it asks nothing of you afterwards.

Buy the copper second, and only once you have noticed yourself grating daikon every week. Buy the bamboo third, because it is cheap and it does something none of the others can. Buy the sharkskin only if there is fresh wasabi in your refrigerator.

And when you are looking at that copper paddle and wondering whether ¥10,450 can be right for a piece of metal with a handle, remember what the maker will charge to put new teeth on it: exactly half. They have already told you which half you were buying. The rest of the Japanese table tends to work the same way — the grooves in the suribachi, the hollow that runs the length of a renge, the foot ring under a donabe. The part that does the work is rarely the part in the product photograph.

Disclosure: Nagori Ware is an independent editorial guide written from Japan. Some links elsewhere on the site are affiliate links. Parts of this site are drafted with AI assistance and checked against Japanese sources. The photograph is AI-generated and illustrative. General information, not legal or safety advice. Prices are what Japanese makers and shops listed in August 2026 and change over time; the pungency of a vegetable is a matter of taste, not of food safety.