An abrasives company that happens to make the stones chefs want

Naniwa is the old name for Osaka. It was the seat of the imperial capital in the seventh and eighth centuries, it survives as a ward of the modern city, and since 1941 it has also been the name of an abrasives firm working in the middle of it.

That word matters. Naniwa Abrasive is not a knife company that also sells stones. Its business is the controlled removal of material, across cutting, grinding, sharpening, polishing and engraving, and sharpening stones are one family of products inside it. Nothing here is quarried and nothing arrives with a romantic provenance. The grain and the binder are chosen deliberately for a job, and the catalogue is laid out as a ladder rather than a collection. It is a small operation, roughly fifty people, still headquartered in central Osaka.

The binder is the whole story

Most synthetic water stones hold their abrasive in resin or in a vitrified clay body. The Chocera Pro stones use neither. The abrasive is aluminium oxide and the binder is a magnesia cement, magnesium oxide, and that one decision is the reason the line has the reputation it has. It cuts quickly, it wears slowly, and it needs almost no preparation. Splash water across it and start.

It also comes with a rule worth knowing before you spend the money. Never leave a Chocera Pro stone soaking. A few seconds under the tap, or a spray bottle, is the entire ritual. Magnesia cement does not tolerate standing water, and a stone left in a tub overnight does not come back. Every other line Naniwa makes is more forgiving about this. The Pro stones are not.

Four tiers, sorted by who is holding the knife

Naniwa names its tiers after the user rather than the stone, which makes choosing easier than the grit charts suggest.

Pro sits at the top, and holds two quite different things. Chocera Pro is the magnesia bonded line described above. Diamond Pro is diamond abrasive set in hard resin on a metal plate, for powder steels and ceramics that a conventional stone will barely mark.

Advance is the line Naniwa sold for years as the Super Stone. Resin infused, genuinely splash and go, and the widest grit range in the catalogue at 220 through 12,000. This is where to look at the polishing end.

Standard is the traditional soaking stone. A few minutes in water, the familiar feel of a classic Japanese water stone under the blade, and a gentler price.

Basic is the combination stones, coarse on one face and fine on the other, for someone who wants one stone rather than a shelf of them.

If you came here looking for Chosera

You are in the right place. This line has been sold as Chosera, as Chocera, and as Naniwa Professional, and all three spellings are still out there in reviews and forum threads written years apart. It is one line. Naniwa's own current name for it is Chocera Pro, and it sits at the top of the Pro tier.

What we carry

We stock the ladder rather than a handful of popular grits, so you can begin where you are and work up without changing brands partway. Chocera Pro from 400 to 10,000. Advance from 220 to 12,000, in single grits and combinations. Standard and Basic beneath them, and Diamond Pro for the steels that need it. The Aotoshi green brick sits slightly outside all of this and has its own following.

We also carry the parts nobody thinks about until the moment they need one: flattening stones to bring a dished surface back true, nagura for dressing, a holder and a sink bridge, and a leather strop for the last pass.