How to Maintain Japanese Knife: Complete Guide to Cleaning and Care

1. How to properly clean a Japanese knife?

Keeping your Japanese knife clean is the first and most important step in proper maintenance. Here’s how you can wash and care for it to prevent rust and stains.

1. Wash by hand only

• Never put your knife in a dishwasher, the heat and harsh detergents can ruin the blade.
• Wash immediately after use with warm water and mild dish soap.

This is especially important if you’ve just cut acidic foods such as tomatoes, lemons, or vinegar-based ingredients. The acids can quickly react with the steel surface and cause pitting or tiny rust spots, particularly on carbon steel blades like Aogami or White #2. Prompt hand-washing removes those residues before they damage the edge or finish.

2. Dry immediately

• Use a soft, dry towel right after washing.
• Never air-dry, as moisture can cause rust and stains.

If your knife has already developed rust, you can check out the detailed guide in the article how to get rust off Japanese knife

3. Avoid abrasive scrubbers

• Steel wool or metal pads will scratch the finish or mirror polish on the blade
• Use a soft sponge or cotton cloth instead.

2. Japanese Knife Maintenance: Storage and Sharpening

Maintaining a Japanese knife is about protecting both its sharpness and its lifespan. Beyond simple washing, the key is regular sharpening, safe storage, and using for the correct purpose that ensures your blade stays strong and reliable for years. If you’re not yet familiar with sharpening, you can read more in the Japanese knife sharpening guide.

1. Sharpen regularly

• Frequency depends on use, every 2–3 months for frequent cooks.
  
• Use a whetstone (waterstone) for best results. Honing rods are not ideal for Japanese blades.

Why you shouldn’t use a honing rod on Japanese knives

A honing rod, especially coarse steel or ceramic types, applies concentrated pressure on the thin edge and hard blade (high HRC) of Japanese knives. This often leads to micro-chipping or edge deformation. In contrast, a whetstone removes material in a controlled way, preserving the proper edge geometry and maintaining long-lasting sharpness.

2. Store properly

• Never toss your knife into a drawer; it will chip the blade.
  
• Instead, use a wooden knife block, magnetic strip, or blade guard.

3. Use for the right purpose

• Japanese knives are designed for specific tasks (slicing sashimi, chopping vegetables, etc.).
  
• Never use a thin slicing knife for cutting bones or frozen food.

3. How to Take Care of a Japanese Knife: Expert Tips

Caring for a Japanese knife is not only about keeping it clean and sharp, it’s about adopting daily habits that protect the blade and handle from damage. From choosing the right cutting board to avoiding very hard foods and preventing rust, these expert tips summarize the essential ways to extend the life of your knife.

1. Avoid cutting very hard foods

Avoid cutting bones, frozen foods, or hard seeds. Japanese knives have thin, hard edges (HRC ~60+) designed for precision, not heavy impact. Striking dense items can chip or crack the blade—even avocado pits or chicken bones. Use gyuto or santoku for vegetables, fish, and boneless meats, and switch to a cleaver or Western-style chef’s knife for tougher tasks.

2. Use the right cutting board

• Glass or stone boards dull the knife quickly.
  
• Use wooden or soft plastic cutting boards for longer edge life.

The USDA Food Safety and Inspection Service highlights that wood and non-porous surfaces like plastic, marble, or pyroceramic are recommended from a food safety perspective, and any cutting board should be replaced once it becomes excessively worn or grooved.

3. Apply oil for rust protection (if needed)

For carbon steel knives (not stainless), apply a thin coat of food-grade mineral oil to prevent oxidation. After testing different oils, we’ve found food-grade mineral oil leaves no aftertaste and provides lasting protection. For the knife handle, you can find the most suitable oils in our guide to the best oils for Japanese knife handles.

Note: Stainless steels like VG-10 or SG2/R2 offer much better corrosion resistance, but you still need to dry them thoroughly after washing to protect the edge and finish.

4. Don’t soak in water

Avoid soaking your knife. Leaving a Japanese knife submerged in water can quickly damage both the blade and the handle. Prolonged moisture exposure causes wooden handles to swell, crack, or loosen from the tang, while the steel blade is at high risk of rust and discoloration. Instead, wash promptly by hand, dry immediately, and store the knife in a dry environment.

4. Common Mistakes When Caring for a Japanese Knife

Even with the best intentions, many people make simple mistakes that shorten the life of their Japanese knives. Here are the most common errors to avoid:

• Using the dishwasher: exposes the knife to high heat and harsh detergents, leading to warping, chips, or even handle cracks.
  
• Air drying: leaves water spots on the blade and encourages rust.
  
• Incorrect sharpening: damages the edge geometry and makes the knife dull faster.
  
• Using the knife for the wrong task: such as cutting bones or frozen food, which often causes chips and breakage.

5. Conclusion 

Learning how to maintain a Japanese knife is not just about making it last longer, it’s also about honoring the craftsmanship and culture behind it. With simple daily habits like washing right after use, drying carefully, and storing it properly, you’ll keep your blade sharp, safe, and a joy to cook with for years to come, and with the trusted quality of Kasumi Japan, every step of care becomes an investment in both tradition and performance.