How to Sharpen a Japanese Knife: Step-by-Step Guide for Home Cooks

Japanese knife sharpening is the process of restoring the edge of Japanese kitchen knives using proper angles and tools like whetstones. A sharp edge helps you slice cleanly through fish, vegetables, and meat without damaging the texture. However, not all sharpening methods are suitable for all Japanese knives. The steel is harder, and the angles differ from those of Western blades. 

In this guide, you’ll learn: 

• How to sharpen Japanese knives correctly at home
• Which tools to use
• How to avoid common mistakes that ruin the blade.

Keep reading to bring your knife back to life and cut like a pro.

What is a Japanese Knife?

Before you start Japanese knife sharpening, you need to know how a Japanese knife is built. Each part of the knife affects how you sharpen it and how it performs in the kitchen.

Parts of a Japanese Kitchen Knife

Japanese Knives, or Wa-bocho, consist of several key parts:

• Blade: The cutting surface. Usually thin and hard, it allows precise cuts.
• Spine: The top, dull edge of the blade. It adds strength and balance.
• Bevel: The angled edge that forms the cutting surface. Can be single or double.
• Heel: The rear part of the blade, closest to the handle. Good for tough tasks.
• Tip: The point of the knife. Useful for detailed cutting and slicing.

Bevel Types: Single vs. Double

Japanese knives usually have two types of bevels:

• Single bevel: Only one side of the blade is sharpened. Found in knives like Yanagiba or Usuba. These require advanced sharpening skills and are often used by professionals.
• Double bevel: Both sides are sharpened, forming a symmetrical edge. Common in Gyuto, Santoku, and Petty knives. Easier to sharpen at home.

Japanese Steel and Hardness

Most Japanese knives use hard steel like White Steel (Shirogami) or Blue Steel (Aogami). Others use stainless options like VG-10 or SG2.

• Hard steel holds a sharp edge longer.
• But it chips more easily if you sharpen wrong or use poor technique.

Because of this, Japanese knife sharpening needs more control and attention than sharpening softer Western blades. You should use a proper whetstone and stick to the right angle, usually around 15 degrees.

Essential Tools for Sharpening Japanese Knives

If you want to get the best result from Japanese knife sharpening, you need the right tools. Japanese knives use harder steel, so you need sharpening tools that match the blade material and geometry.

1. Whetstones (Water Stones)

Japanese knives work best with water stones. These stones use water to remove steel and reshape the edge.

• Coarse (200–800 grit): For repairing chips or very dull edges. Use only when needed.
• Medium (1000–3000 grit): Best for regular sharpening. Suitable for most home cooks.
• Fine (4000–8000 grit): For refining the edge and improving cutting performance.
• Polishing (>8000 grit): Used by professionals to get a mirror finish. Not required for everyday use.

2. Stone Preparation

Before sharpening, soak most whetstones in water for 10–15 minutes.

• Soak time: Some synthetic stones need full soaking. Splash-and-go stones don’t.
• Flattening: Use a correction stone or lapping plate to keep the stone surface flat.
• Cleanup: Rinse off metal particles between sessions to avoid clogging the grit.

3. Additional Tools

Moreover, you also need to prepare additional tools, including:

• Non-slip mat or stone holder: Keeps the stone stable and reduces the risk of injury.
• Honing rod (ceramic only): Helps align the edge between sharpening sessions. Don’t use steel rods on Japanese knives—they’re too hard.
• Angle guide: Helps beginners keep a consistent sharpening angle. Especially useful for 15° angles on double bevel knives.

Recommended Sharpening Stones

Note: Using the right grit helps maintain your knife without shortening its lifespan. If you’re new to sharpening Japanese knives, a combo stone with 1000/6000 grit is a great place to start.

Step-by-Step Guide to Sharpening a Japanese Knife

You don’t need to be a professional to sharpen a Japanese knife. You just need the right tools, angles, and a few consistent techniques. This guide walks you through each stage.

Step 1: Prepare Your Knife and Whetstone

Before sharpening, you should get your tools ready.

1. Soak your water stone for 10–15 minutes. If bubbles stop rising, it’s fully saturated.
2. Clean your knife with water and wipe it dry.
3. Place the whetstone on a non-slip surface, like a damp cloth or rubber base.

Step 2: Check the Blade Condition

Next, choose the right grit based on the level of dullness or damage to your knife edge.

• Use #400–#800 grit for dull or chipped edges.
• Choose #1000–#3000 grit for regular maintenance.
• Finish with #6000–#8000 grit if you want a polished, razor-sharp edge.

Step 3: Hold the Right Angle

Then, holding the correct angle is key to clean sharpening.

• Use a 10°–15° angle for double bevel knives (like Gyuto, Santoku).
• Use a 10°–12° angle for single bevel knives (like Yanagiba).

Note: Place two fingers on the flat part of the blade and hold the handle firmly to guide each stroke.

Step 4: Sharpen One Side First

After that, you sharpen one side first. Work from the heel to the tip of the blade.

• Push the blade across the stone using a smooth, sweeping motion.
• Keep your angle steady and apply even pressure.
• Repeat this motion 10–15 times per section.

Note: After sharpening the full edge, gently feel the opposite side for a burr (a small ridge).

Step 5: Switch Sides and Repeat

Once the burr appears:

• Flip the knife and sharpen the other side the same way.
• Use the same number of strokes to keep the edge balanced.

Note: Check for even burr formation to confirm both sides are sharpened equally.

Step 6: Refine the Edge

You use a polishing stone or high-grit stone to refine the sharpness.

• Lighten the pressure as you go.
• Make alternating strokes on both sides to smooth out the edge.

Step 7: Clean and Store the Knife

The last, post-sharpening care is as important as the sharpening itself.

• Rinse the knife and stone with water to remove metal particles.
• Dry your knife completely, especially near the spine and handle.
• Store the knife in a sheath, magnetic strip, or block to protect the edge.

Expert Tip: After testing, we recommend that you don’t count strokes. Feel the burr. Once the burr appears, your edge is ready; sharpening beyond that only removes steel and shortens knife life.

Safety Practice Tips While Sharpening Knife

Sharpening a Japanese knife at home may damage the knife or leave you injured. If you don't follow a few key rules below:

1. Use a stable surface

Set your whetstone on a non-slip mat or a damp towel. A moving stone can cause your knife to slip.

2. Position your hands correctly

Keep your fingers above the spine of the blade. Avoid placing fingers near the edge. When guiding the knife, press gently with your non-dominant hand, but never touch the edge directly.

3. Work slowly and with control

Don’t rush. Use smooth, consistent strokes. It’s better to go slow and steady than to risk slipping or cutting yourself.

4. Keep your sharpening area dry and clutter-free

Wipe away water and stone residue often. A clean surface reduces the chance of slipping.

5. Check for sharpness using safe methods:

• Paper test: Hold a sheet of paper and slice downward. A sharp knife should cut cleanly without tearing.
• Tomato test: Try slicing a ripe tomato without pressure. If the blade glides through the skin easily, the knife is ready.
• No-finger test: Never check sharpness with your finger. Use visual or material-based methods only.

Common Mistakes to Avoid

Sharpening Japanese knives takes practice. Many beginners make small mistakes that can damage the blade or reduce its sharpness. Here are the most common ones and how to avoid them:

• Using the wrong angle.
  You should keep the sharpening angle consistent, around 15° for double bevels, 10°–12° for single bevels. An uneven angle will ruin the edge.
• Choosing the wrong stone grit.
  Don’t start with a coarse stone unless you need to fix chips. For regular sharpening, use a medium grit (around 1000). Finish with a fine stone (3000–8000) for a smoother edge.
• Rushing the process.
  Go slow and use controlled strokes. Speed does not improve sharpness. It increases the risk of slipping and damaging the blade.
• Applying too much pressure.
  Heavy pressure can wear down the edge of the stone unevenly. Let the stone do the work.
• Skipping burr detection.
  If you don’t feel for the burr after sharpening one side, you won’t know if the edge is ready to flip. This step matters for getting a clean, even edge.
• Sharpening a dirty or wet handle.
  Keep the handle dry. A wet grip can slip easily during sharpening.

Lewis Knife recommends: Always practice with an inexpensive knife before sharpening a premium Japanese blade. It helps you build confidence without risking your best tools. And always check your angle and stroke rhythm before starting.

Final Words

Japanese knife sharpening helps you maintain the edge, balance, and performance that make these blades stand out. With the right technique and tools, you can extend the life of your knife and improve every cut. Start with basic whetstone sharpening, keep a consistent angle, and sharpen only as needed.