Sharpening
What angle for a Japanese knife
Why Japanese knives are sharpened at 15 degrees per side when European knives sit at 20, what that changes, and what destroys the angle.
A sharpening angle is not an aesthetic preference, it is a trade-off between two things that pull against each other: how fine the edge is, and how well it holds.
The firmer the angle, the thinner the edge, and the less force it takes to enter the food. But a thin edge rests on less material: it rolls or chips sooner. That is the whole problem.
15 against 20 degrees
European cutlery traditionally works around 20 degrees per side. Japanese cutlery, around 15. The difference is not cultural, it follows from the steel.
A classic European steel is hardened to around 56 HRC. At that hardness an edge at 15 degrees does not hold: it deforms. At 20 degrees it has enough material behind it to take the load.
A steel like VG10, up at 60-61 HRC, carries a fine edge without folding. It can therefore be given 15 degrees, and repay it with a distinctly cleaner entry into the food.
What those five degrees change in the kitchen
The difference shows on anything that resists at the surface: the skin of a tomato, of a pepper, the thin membrane on a chicken breast. At 20 degrees the blade crushes for an instant before it goes in. At 15, it goes in.
On a julienne it shows as batons that do not stick together: the edge severs the fibre instead of pushing it.
What destroys that angle
Pull-through sharpeners. Their guides are fixed, almost always at 20 degrees or more. Running a Japanese blade through one reforms a more obtuse bevel than the original, removing a lot of material along the way. Three seconds are enough to erase the workshop’s grind.
Ribbed steel honing rods. They are designed to straighten thick edges. On a fine, hard edge they tear out micro-chips. A ceramic rod, held at the blade’s angle, does the job without breaking anything.
Inconsistency. A 15-degree grind is only worth anything if it is even along the whole length. An angle guide clipped on the spine beats a steady hand you do not yet have.
In practice
A double-bevel Japanese blade is brought back at around 15 degrees per side, on a water stone, grit 1000 then 3000, keeping the angle constant. There is nothing else to remember.
Frequently asked
Is a Japanese knife sharpened at 15 degrees on both sides?
For a double-bevel blade such as a gyuto, a santoku or a nakiri, yes: 15 degrees each side, so 30 degrees of total angle. Single-bevel blades, like a traditional yanagiba, follow a different logic.
Can I sharpen my European knife at 15 degrees?
It is possible if its steel is hard enough, but a steel at 56 HRC ground too finely will chip. Stay at 20 degrees on that kind of blade.
How do I know the angle my knife is sharpened at?
The maker almost always states it. Failing that, mark the bevel with a felt pen and take one pass on the stone: the erased trace shows where the angle bears.
Whetstone 1000 / 3000 — The only sharpener that suits a 15 degree edge.
A 15 degree edge is restored on a stone, not on a steel. Ours is built for that angle.
Whetstone 1000 / 3000Read next
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