This is the first question anyone asks when they are about to sharpen a knife, and it is also where most mistakes are made. Choosing the wrong sharpening angle won't ruin a blade in one go, but repeated over several years, it can turn a good knife into a mediocre tool.
The short answer
20° for a European knife. 15° for a Japanese knife. If you don't know where your knife comes from, use 20°: it's the most common angle in French kitchens, and it won't weaken any blade.
Why the angle changes everything
The sharpening angle is the inclination between the stone and the blade. It determines two opposing things: the sharpness of the edge and its resistance.
A shallow angle, around 15°, gives a very fine edge that slices food instead of crushing it. This explains the cutting sensation of a good Japanese knife. However, this edge is fragile: it can chip on a bone, a pit, or a cutting board that's too hard.
A wider angle, around 20°, gives a slightly less biting but significantly more durable edge. This is the compromise adopted by European cutlery for a long time, because a family kitchen knife needs to withstand various uses.
The table by knife type
| Knife | Recommended angle |
|---|---|
| European chef's knife (Sabatier, Wusthof, Zwilling) | 20° |
| Paring knife | 20° |
| Santoku, gyuto, nakiri (Japanese) | 15° |
| Boning knife | 20° |
| Pocket knife, Opinel | 20° |
| Fillet knife | 15° |
| Bread knife (serrated blade) | Not sharpened in this way |
A clarification that avoids a common confusion
When we talk about 20°, we mean the angle per side. Since the knife is sharpened on both sides, the total edge angle is 40°. Some manufacturers state the total angle, others the angle per side. If you read 30° somewhere and 15° elsewhere for the same knife, this is probably what it's about.
Should you respect the original angle?
Yes, as much as possible. A knife leaves the factory with a given angle, and re-sharpening it to the same angle requires little material removal and little time. Changing the angle means reshaping the entire bevel, which involves many passes on a coarse grit.
One case justifies changing: a Japanese knife that you use intensively and that chips often. Changing it to 18 or 20° will give it a more durable edge, at the cost of a little sharpness.
The real problem isn't choosing the angle, it's maintaining it
Knowing that you need 20° is not enough. On a freehand sharpening stone, you need to reproduce this angle over a hundred consecutive passes. A deviation of a few degrees from one pass to the next produces an irregular edge, rounded in places, and the knife cuts less well than before you touched it.
This is why guided-angle sharpeners have been developed: the angle is no longer in the wrist, it's in the tool. This is also the principle of the KUTO roller knife sharpener, whose block has two molded notches at 15° and 20°: you place the blade, it automatically settles, and the angle remains identical from the first to the last pass.
To remember
- 20° per side for the vast majority of European kitchen knives.
- 15° per side for Japanese knives and thin blades.
- When in doubt, 20°: you take no risks.
- Respect the original angle rather than changing it.
- The difficulty is not choosing the angle, but maintaining its consistency.