How to Sharpen a Knife with a Whetstone: A Beginner's Guide
A whetstone is the best way to sharpen a kitchen knife at home. Pull-through sharpeners and electric grinders remove too much metal and leave a rough edge. A whetstone lets you control the angle, pressure, and how much material you remove. You end up with a sharper edge that lasts longer.
This guide covers the full process, from soaking the stone to testing your edge. If you have never sharpened a knife before, start here.
What You Need Before You Start
- A whetstone: A dual-sided stone with a coarse grit (around 1000) and a fine grit (around 3000-6000) covers most situations. Our Yuzu Dual-Sided Whetstone works well for this.
- A towel: Place it under the stone to stop it sliding around.
- Water: For soaking and lubricating the stone during sharpening.
- Your knife: Any kitchen knife works. Japanese knives with harder steel respond particularly well to whetstone sharpening.
That is it. No jigs or guides needed.
Step 1: Soak Your Whetstone
Submerge the stone in water for 10-15 minutes. You will see small bubbles rising from the surface. Once the bubbles stop, the stone is fully saturated and ready to use.
A soaked stone creates a slurry of fine abrasive particles as you sharpen. This slurry does most of the work, so do not skip this step. Keep a small bowl of water nearby to splash on the stone if it dries out.
Place the wet stone on a folded towel, coarse side (lower grit number) facing up.
Step 2: Find Your Sharpening Angle
The sharpening angle determines the shape of your cutting edge. For most kitchen knives:
- Japanese knives: 12-15 degrees per side
- Western knives: 18-22 degrees per side
Fifteen degrees is roughly the height of two stacked coins under the spine when the edge sits flat on the stone. If your knife came sharpened at a specific angle (Yuzu knives are factory-sharpened at 15 degrees), stick with that angle.
The marker trick: Draw along the edge bevel with a permanent marker before you start. After a few strokes on the stone, check where the marker has been removed. If it is gone evenly across the bevel, your angle is correct. If only the top or bottom of the bevel is bare, adjust accordingly.
Step 3: Sharpen the First Side
Hold the knife handle in your dominant hand. Place two or three fingers of your other hand flat on the blade, near the edge. These fingers provide pressure and help you keep the angle consistent.
Push the blade away from you along the stone, edge leading, from the heel of the knife to the tip. Use the full length of the stone. Apply moderate, even pressure on the forward stroke and lighten up on the return stroke.
Work in sections if your knife is longer than the stone:
- Start with the heel section (closest to the handle). Do 10-15 strokes.
- Move to the middle of the blade. Another 10-15 strokes.
- Finish with the tip. 10-15 strokes, lifting the handle slightly to follow the curve.
Keep the stone wet. Add water whenever the surface starts to look dry or the slurry thickens too much.
Step 4: Feel for the Burr
After sharpening one side, run your thumb gently across the edge (not along it) from the spine toward the cutting edge on the opposite side. You should feel a slight rough catch along the entire length. This is the burr, a thin ridge of metal that forms when you have sharpened one side enough to push metal over.
If you feel the burr from heel to tip, that side is done. If there are gaps, go back and give those sections more strokes.
The burr is your progress indicator. No burr means you have not sharpened enough. A burr along the whole edge means it is time to flip the knife.
Step 5: Sharpen the Second Side
Flip the knife over and repeat the same process on the other side. Same angle, same number of strokes per section. You are now sharpening until the burr transfers back to the first side.
For double-bevel knives (which includes most kitchen knives and all Yuzu knives), aim for equal work on both sides. This keeps the edge centred.
Single-bevel knives are different. If you have a yanagiba or usuba, the flat side (ura) gets only a few light strokes to remove the burr. Most of the sharpening happens on the angled side (shinogi). If you are not sure which type you have, check whether both sides of the blade are angled near the edge. If yes, it is double-bevel.
Step 6: Move to the Fine Grit
Flip your stone to the fine grit side (higher number, smoother surface). If you are using separate stones, switch to your finishing stone now.
Repeat the sharpening process on both sides, but with lighter pressure and fewer strokes (5-10 per section). The fine grit polishes the edge and removes the micro-scratches left by the coarse grit. This is what gives you a clean, sharp edge that glides through food.
After the fine grit, the burr should be barely there. A few very light alternating strokes (one per side) will remove it completely.
Step 7: Test Your Edge
Three simple ways to check if your knife is sharp:
- Paper test: Hold a sheet of paper by one edge and draw the knife downward through it. A sharp knife cuts cleanly without catching or tearing.
- Tomato test: Rest the knife on a ripe tomato and press down gently. A sharp blade sinks through the skin under its own weight with minimal pressure.
- Fingernail test: Lightly place the edge on your fingernail at an angle. A sharp knife catches and grips. A dull one slides off. Be careful with this one.
Sharpening a Gyuto Knife
The gyuto has a gentle curve toward the tip that makes sharpening slightly different from a flat-edged knife like a nakiri. You need to lift the handle gradually as you move from the heel to the tip, following that curve so the stone contacts the full edge.
Sharpen at 15 degrees per side (the factory angle for most Japanese gyutos, including Yuzu's). Use the marker trick to confirm you are hitting the full bevel. The curved section near the tip is where most people lose their angle, so slow down there and check your work.
Gyutos see heavy use across meat, fish, and vegetables, so they dull faster than specialist knives. A quick touch-up on the fine grit every 2-3 weeks keeps the edge performing. Full sharpening on both grits every 2-3 months is enough for most home cooks.
Common Mistakes and How to Avoid Them
Changing angle mid-stroke. This rounds over your edge instead of sharpening it. Lock your wrist and move from your shoulders, not your hands. The angle stays consistent when the motion comes from your arms.
Too much pressure. Pressing harder does not sharpen faster. It removes more steel than necessary and can dish the stone unevenly. Moderate, consistent pressure works better.
Skipping the coarse grit. If your knife is dull, start on the coarse grit. Jumping straight to a fine stone when the edge is damaged means spending ages on a stone that was not designed for material removal.
Not sharpening often enough. A quick touch-up on the fine grit every few weeks takes five minutes and keeps your knife performing well. Waiting until the knife is dull means a longer session on the coarse grit to rebuild the edge. Little and often beats marathon sessions.
Using a dry stone. Always soak before use and add water during sharpening. A dry stone clogs with metal particles and scratches your blade instead of cutting cleanly.
How Often Should You Sharpen?
It depends on how much you cook. As a rough guide:
- Daily cooking (home cook): Sharpen on the fine grit every 2-4 weeks. Full sharpening (both grits) every 2-3 months.
- Heavy use (professional): Fine grit touch-up weekly. Full sharpening monthly.
- Occasional cooking: Full sharpening every 4-6 months, or whenever the knife stops cutting cleanly.
Japanese knives made from harder steel, like the AUS-10 steel used in Yuzu knives, hold their edge longer than softer Western stainless steel. You will notice you can go longer between full sharpening sessions.
Caring for Your Whetstone
After each use, rinse the stone under running water to remove the metal-laden slurry. Let it air dry completely before storing. Never leave a whetstone soaking permanently, as some stones can crack.
Over time, the centre of the stone will dish (become concave) from repeated use. A flat stone is important for consistent angles. When you notice dishing, flatten the stone by rubbing it against a flattening plate or a piece of wet-dry sandpaper on a flat surface.
Conclusion
Whetstone sharpening is a skill, and the first time is the hardest. Your angle will wander, you will second-guess the pressure, and the burr might take longer to form than you expect. That is normal. By your third or fourth session, muscle memory kicks in and the whole process takes under ten minutes.
A sharp knife is safer, faster, and more enjoyable to use. Once you have done it yourself, you will not want to go back to pull-through sharpeners. For a more detailed walkthrough of whetstone use including grit selection, see our full whetstone guide.
