How to Sharpen Your Japanese Knife: A Beginner’s Guide

A well-sharpened knife changes the rhythm of cooking. Cuts feel cleaner, movements feel lighter, and the work at hand becomes more focused.

Japanese knives are valued for their sharpness and beauty, but also for how naturally they invite care through use. With proper sharpening, they continue to perform as intended. While this may feel like a challenge at first, understanding a few basic steps is often enough to restore a fine edge at home with confidence.

In this article, we will walk beginners through how to sharpen a basic double-bevel Japanese knife using a traditional natural whetstone, with instructions starting from how to prepare your whetstone to essential sharpening techniques. Experience the satisfaction of bringing a lifelong tool back to peak condition with your own hands.

A sharp knife changes the entire cooking experience. Instead of pushing and sawing through ingredients, the blade moves smoothly with minimal effort. This reduces strain on your hands, prevents food from tearing, and makes each cut more precise. A sharper edge is also safer because the knife is less likely to slip.

While there are many types of whetstones available, in this guide, we use a natural whetstone. Western-style knife sharpeners can temporarily sharpen the edge, but using a whetstone is recommended as it sharpens the knife in a way that follows the original shape of the blade. In general, Western pull-through knife sharpeners are not recommended for Japanese knives, as they remove metal quickly and can wear down the edge over time.

Whetstones are identified by a grit number, shown with a # sign, such as #220 or #1000. This number refers to the grit size, or how coarse the stone is. Lower numbers are rougher, while higher numbers are finer. The grit number is usually printed on the stone or its packaging. For beginners, a medium-grit whetstone around #1000 is the most practical choice, as it is ideal for regular sharpening and restoring a dull edge.

Used to place under the stone to keep it from sliding. A towel also helps catch water and metal filings.

Helpful for adding small amounts of water to the stone as the whetstone will gradually dry out during sharpening.

Wipe away any residue or moisture on your knife. A clean surface allows the knife to make full contact and keeps your whetstone clean as well. 

Submerge the whetstone in water for about twenty minutes. You will see air bubbles rise from the stone as it absorbs water. Check the surface of the stone for a thin layer of water.

A properly moistened stone improves the feel of the blade and allows the abrasive particles to work evenly in the thin layer of water on the surface.

These steps focus on a basic double-bevel knife, the most common style for beginners. The method applies to gyuto, santoku, and Japanese petty knives.

Place the soaked whetstone on a damp towel atop a flat, dedicated surface. It must not move once you begin sharpening. Working on an unstable kitchen top may lead to injuries or damage to your knife.

Set the bowl of water nearby in case you need to add water to the whetstone.

Start by sharpening the side facing away from you as you hold the knife in your dominant hand. Position the blade so that it rests at about a 25–30° angle from the side of the whetstone. Work at this position as you sharpen. Place your thumb on the heel and your index finger on the spine, and grip the handle with the rest of your fingers to make sure the knife does not wobble.

Next, lift the spine so that the cutting edge of the blade is at about 15° from the whetstone’s surface. In Japan, the general rule is that the thickness of two coins fits between the spine and the whetstone. This setting helps sharpen the knife effectively while maintaining its original shape.

To start sharpening, place two or three fingers from your non-dominant hand on top of the blade and push the knife away from your body across the stone, and then lightly pull it back. If the stone begins to dry, add a little water, as the natural slurry can help smooth out microscopic serrations. 

Work gradually from the tip to the heel. Some beginners find it helpful to divide the blade into three sections: heel, middle, and tip. As a guideline, repeat the forward and back motion about twenty times for each section. This reduces the tendency to rush through the process and helps you pay attention to how the blade feels at each point.

As you sharpen the blade, metal will fold over into a thin ridge called a burr (bari or hakaeri in Japanese). You can feel this by gently brushing your fingertip on the edge, moving from the spine toward the cutting edge. If you feel a slight roughness, the burr has formed.

The burr is important because it confirms that you have reached the very edge of the knife. Without raising a burr, the sharpening process is incomplete.

Next, move to the other side of the blade.

Flip the blade so that the spine is facing you, and adjust the handle so the blade is at roughly a 70–80° angle from the whetstone (the handle will be further away from the side edge of the stone). Working from heel to tip, sharpen this side using about the same number of strokes to keep the blade balanced. Once again, set the cutting edge at a 15° angle. 

Beginners often find that the second side feels slightly different. This is normal. The goal is simply to sharpen until the burr transfers to the opposite side.

If you are left-handed, do the mirror image of what is shown in each photograph. The angles in relation to the whetstone don’t change; only the hand with which you hold the knife.

After both sides have raised and removed a burr, finish with one light stroke on each side. With the spine lifted to about a 25–30° angle (four coins between the blade and the whetstone’s surface), use minimal pressure and let the front side of the knife glide from tip to heel, going from the bottom to the top of the stone in a single, gentle sweep. Do the same for the back side of the knife, but this time go from heel to tip and sweep from top to bottom. This final pass helps clean up the edge and remove any remaining roughness.

Rinse the knife with water and dry it thoroughly. Do not leave moisture on the blade, especially on knives made from carbon steel or partially carbon cores.

Rinse your stone as well. Wipe off residue and allow the stone to dry fully before storage.

Your knife should now feel noticeably sharper. It should slice through ingredients with ease. Over time, as your technique improves, your edge will become even more refined.