Sharpen a kitchen knife with a whetstone

A sharp knife is safer than a dull one: it goes where you aim it instead of slipping.

You need: a combination whetstone (around 1000 grit on one side, 3000 to 6000 on the other) and a damp towel.

1. Soak the stone in water for 10 minutes (unless it says "splash and go").
2. Put it on the damp towel so it can't slide, coarse side up.
3. Hold the knife at about 15 to 20 degrees to the stone. Two stacked coins under the spine is roughly right.
4. Push the blade across the stone, edge first, sweeping from heel to tip. Keep the angle steady. Do about 10 strokes.
5. Feel the other side of the edge with your thumb (across it, never along it). When you feel a slight rough lip, called a burr, along the whole length, flip the knife and do the other side.
6. Switch to the fine side and repeat with lighter pressure, fewer strokes.
7. Finish with a few alternating single strokes on each side, then rinse and dry the knife.

Test: it should slice a sheet of paper cleanly. Most home knives only need this a few times a year.