A knife that crushes a tomato instead of slicing it isn't worn out: it has lost its edge. A whetstone brings it back in about ten minutes. It sounds technical, but it comes down to three things: a wet stone, a steady angle, and a signal you can feel with your finger.
What each grit does
The number on a stone tells you how fine its abrasive is. The lower it is, the more metal it removes.
- 1000 grit: sharpening. It rebuilds the edge. You always start here on a dull knife.
- 6000 grit: finishing. It polishes the edge and removes the micro-serrations left by the 1000. The knife goes from sharp to razor sharp.
- Below 1000 (240, 400): repair. Only needed for a chipped or badly damaged blade.
A double-sided 1000/6000 stone therefore covers the normal upkeep of a kitchen knife.
Before you start
- Soak the stone for 10 minutes until no more bubbles rise. A water stone must work wet: the water mixes with stone dust into a slurry that does the sharpening.
- Set it on its base, 1000 side up, on a stable surface. A damp towel underneath stops any sliding.
- Keep a glass of water nearby to wet the stone whenever it dries.
Finding the angle
Our knives are factory-sharpened at 15° per side. That is the angle to reproduce. The angle guide that clips onto the spine does it for you at first.
Without a guide, a simple trick: hold the blade at 90° to the stone, halve it (45°), halve it again (about 22°), then lower it a little. You are around 15°. In practice, the spine sits roughly two stacked coins above the stone.
The exact number matters less than consistency: a slightly different angle held all the way gives a better edge than a perfect angle that changes with every stroke.
Sharpening on the 1000 side
- Edge facing you, blade at 15°, two or three fingers of the other hand resting flat on the blade near the edge.
- Push the blade forward along the full length of the stone with light pressure, then bring it back without pressing. Work in sections: heel, middle, then tip, turning the wrist slightly on the curved part.
- Ten to fifteen strokes per section, then check for the burr.
The burr, the only signal that matters
As you sharpen one side, you push a tiny sliver of metal over to the other side of the edge: that is the burr. Run your thumb over the other side, across the edge, from spine to edge, never along it. If it catches slightly, like a little stubble, the burr is there.
When you can feel it along the whole blade, that side is done. Turn the knife over and do exactly the same on the other side until you feel the burr again.
Finishing on the 6000 side
- Flip the stone and wet it.
- Same angle, even lighter pressure. Five strokes on one side, five on the other.
- Then three and three, then one and one, alternating. These shorter alternating passes remove the burr instead of just moving it.
The test
A sheet of paper held by one corner: the blade should slice it without snagging. Or a tomato: rest the blade on the skin and draw it without pressing, it should go in on its own.
Rinse and wipe the knife. For a carbon steel blade, such as our Aogami santoku, dry it straight away.
Afterwards: the stone
Rinse it and let it air-dry off its base before putting it away. Over time the middle of the stone dishes out: now and then, rub it flat on sandpaper laid on a very flat surface to level it. A dished stone gives an uneven edge.
What about the honing rod?
The stone rebuilds the edge. The rod maintains it between sharpenings. A diamond rod, like ours, is slightly abrasive: it revives an edge that is starting to fade.
On hard blades (60 HRC and above), use it gently: same 15° angle, three to five very light strokes per side, alternating, never forcing. When the rod no longer does the job, it is time for the stone again.
How often
It depends on use. For a knife used every day: a few passes on the rod when cuts become less clean, and the stone every one to three months. For a weekend knife, two or three times a year is enough. Cutting on a good board spaces sharpenings out a lot: which board to choose.
The tools
1000/6000 whetstone, bamboo base and angle guide — CHF 119
Diamond honing rod, ebony handle — CHF 99
