How to keep a sushi knife sharp for years with 10 minutes of care
By Clare FarnellUpdated 14 May 20268 min read
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A sharp knife is the most important tool in sushi making. Every professional chef knows this. A dull knife tears fish, crushes rice, and turns cutting into a struggle. The difference between a knife that performs well and one that does not is almost always maintenance, not the knife itself.
I have used the same Tojiro Fujitora Gyuto for three years. The blade is as sharp now as the day I bought it. The only reason is a 10-minute sharpening session on a whetstone every 6 weeks and 30 seconds of cleaning after every use. That is the full extent of sushi knife care.
Japanese steel demands more attention than German steel. It is harder, holds a sharper edge longer, but chips if mistreated and rusts if neglected. This page covers every aspect of maintenance so your knife stays in cutting condition for years.
How do you sharpen a sushi knife?
Use a whetstone, not a honing rod. Japanese steel at HRC 60 or higher is too hard for honing rods and can chip. A 1000/3000 grit combination stone handles both sharpening and polishing.
What you need
A 1000/3000 grit combination whetstone ($25 to $40). A stable surface with a damp cloth underneath to prevent the stone from sliding. A bowl of water for soaking the stone. A towel for drying the blade afterward.
The sharpening technique
Soak the stone in water for 10 to 15 minutes until bubbles stop rising. Place it on the damp cloth with the 1000 grit side facing up.
Hold the knife at a 15-degree angle to the stone. For double bevel knives (gyuto, nakiri), sharpen both sides equally. For single bevel knives (yanagiba), sharpen the bevelled side only and give the flat side 2 to 3 light passes to remove the burr.
Draw the blade across the stone from heel to tip in a smooth motion. Apply light even pressure. Repeat 10 to 15 strokes per side. You should feel a slight burr forming on the opposite edge. That burr means steel is being removed and a new edge is forming.
Flip to the 3000 grit side and repeat with lighter pressure. This polishes the edge and removes the burr. The precision of the final edge depends on this polishing step.
Rinse the knife, dry completely, and test by slicing a sheet of paper. A sharp blade cuts cleanly. A dull blade tears.
How often to sharpen
VG-10 steel (Tojiro, most mid-range Japanese knives): every 4 to 8 weeks with weekly use. High-carbon stainless (Victorinox): every 2 to 4 weeks. Carbon steel: every 6 to 10 weeks but requires more rust protection.
How do you clean a sushi knife?
Hand wash with warm water and mild soap immediately after every use. Dry completely with a clean cloth. Never put a Japanese knife in a dishwasher.
The dishwasher is the single fastest way to destroy a Japanese knife. The heat warps handles, the jostling chips the edge against other utensils, and the harsh detergent promotes corrosion on the steel. Even knives labelled "dishwasher safe" last longer when hand washed.
After cutting acidic ingredients like citrus or vinegar-seasoned rice, wash the blade immediately. Acid accelerates rust on carbon steel and can stain stainless steel.
After cutting raw fish, wash with soap to remove oils and bacteria. This is a food safety requirement, not just a maintenance one.
How do you prevent rust and corrosion?
Dry the blade completely after every wash. Moisture left on the steel surface is the primary cause of rust on Japanese knives.
Carbon steel knives
Carbon steel rusts within hours if left wet. Dry immediately after washing. Apply a thin coat of food-safe mineral oil or camellia oil to the blade before storage. The oil creates a protective barrier against moisture in the air. Over time, carbon steel develops a patina (blue-grey discolouration) that actually protects the blade. Do not scrub the patina off.
Stainless and VG-10 steel knives
Stainless steel resists corrosion better than carbon steel but is not immune. Dry after washing. Store in a dry environment. If spots appear, remove them with a mild abrasive like Bar Keeper's Friend and a soft cloth. The durability of stainless steel does not mean zero maintenance. It means less maintenance.
What causes rust
Standing water on the blade surface. Dishwasher humidity. Wet storage in a knife block with poor airflow. Acidic food residue left on the blade. Salt exposure without rinsing. Any of these will start corrosion on even high-quality steel.
How should you store a sushi knife?
A magnetic wall strip, a blade guard, or a knife roll. Never loose in a drawer where the edge contacts other utensils.
Magnetic strip
The best option for daily-use knives. The blade stays visible, accessible, and protected from contact. Mount the strip away from the stove to avoid heat and moisture exposure. Magnetic strips cost $10 to $30 and hold 4 to 6 knives.
Blade guard (saya)
A wooden or plastic sheath that slides over the blade. Essential for transport or drawer storage. Japanese knife guards (saya) are traditionally made from magnolia wood. Plastic guards work equally well for protection.
What to avoid
Knife blocks with slots collect moisture and bacteria inside the slots. If you use a block, store knives blade-up so the edge does not rest on wood. Loose drawer storage causes the edge to contact other cutlery. Every bump dulls the blade and risks chipping. Use a drawer organiser with individual slots if counter space is limited.
The craftsmanship of a quality Japanese knife deserves storage that protects the edge and the balance of the handle. Proper storage is as important as proper sharpening for the long-term quality of the blade.
What mistakes ruin a sushi knife?
Four common mistakes cause most knife damage. All are preventable.
Using a honing rod on Japanese steel. The steel is too hard. The rod chips the edge rather than realigning it. Use a whetstone only.
Cutting on glass, ceramic, or marble surfaces. These materials are harder than the knife blade and destroy the edge instantly. Always use a wooden or plastic cutting board.
Twisting or prying with the blade. Japanese knives are designed for straight cutting and slicing motions. Lateral force chips the thin edge. Never use a sushi knife to pry open containers, cut through bone, or scrape food off a board with the edge.
Putting it in the dishwasher. Already covered above but worth repeating. The dishwasher does more damage in one cycle than months of daily use.
For recommendations on which sushi knife to buy, read the best sushi knives guide. For the complete set of sushi tools including mats, kits, and chopsticks, read the tools hub.
How often should I sharpen a sushi knife?
Every 4 to 8 weeks for VG-10 steel with weekly use. Every 2 to 4 weeks for softer stainless steel like the Victorinox. Carbon steel holds an edge longer at 6 to 10 weeks but requires oil protection against rust between sharpenings.
Can I use a honing rod on a Japanese knife?
No. Japanese knife steel at HRC 60 or higher is too hard for honing rods. The rod will chip the edge rather than realign it. Use a whetstone for all Japanese knife sharpening. Honing rods are only suitable for softer Western steel.
What whetstone grit should I use?
A 1000/3000 grit combination stone covers both sharpening and polishing. The 1000 grit side removes material and creates the edge. The 3000 grit side polishes and removes the burr. This single stone handles all routine maintenance.
How do I prevent my sushi knife from rusting?
Dry the blade completely after every wash. Apply food-safe mineral oil to carbon steel before storage. Store in a dry location on a magnetic strip or in a blade guard. Never leave a wet knife on the counter and never put any knife in a dishwasher.
Can I put a Japanese knife in the dishwasher?
No. The heat warps handles, the jostling chips edges, and the detergent promotes corrosion. Hand wash with warm water and mild soap, dry immediately, and store properly. This applies to all Japanese knives regardless of steel type.
Clare Farnell has been making sushi at home since 2021 and writes about Japanese home cooking, sushi tools, and kitchen equipment at sushi-planet.com.
Last updated: 14 May 2026.