How to Care for Your Japanese Knife

A good Japanese knife is worth looking after. The same properties that make them perform so well - hard steel, thin grinds, acute edge angles - also mean they need a bit more attention than a German knife. None of it is difficult, but a few bad habits can do real damage to a blade that cost serious money.

Here is what you need to know.

Wash by hand, every time

This is the one rule that matters more than any other. Never put a Japanese knife in the dishwasher.

The heat, the harsh detergents, and the rattling around will damage the edge, corrode the steel, and ruin wooden handles. It does not matter how expensive the knife is or how good the dishwasher is. Hand wash only, every time.

Wash with warm water and a small amount of dish soap, wipe with a soft cloth or sponge, rinse and dry immediately. Do not leave it soaking in the sink and do not leave it wet on the bench. Carbon steel in particular will rust quickly if left damp, and even stainless steel can develop spots over time if moisture sits on the blade.

Dry it properly

Wipe the blade dry after washing rather than leaving it to air dry. A clean tea towel works fine. If your knife has a carbon steel core or is fully carbon steel, do this immediately after washing. Leaving water on carbon steel even for a few minutes can start surface rust.

A light patina will develop on carbon steel over time. This is normal and actually helps protect the steel. It does not need to be polished off.

Use the right cutting surface

Wood or plastic boards only. End grain timber is ideal. Edge grain timber is fine. Plastic is acceptable for everyday use.

Avoid glass, ceramic, marble, and slate boards entirely. They look good on a kitchen bench but they will destroy an edge in a single session. Stone and tile surfaces are equally bad. If you are using a Japanese knife on any hard surface, you are undoing your sharpening every time you cook.

Bamboo is harder than most people realise and is not ideal for fine Japanese edges. If you have a bamboo board, it is better used for other tasks.

Store it safely

A knife rattling around in a drawer will chip and blunt quickly, even with a blade guard on. The best options are a magnetic knife strip, a knife block with slots sized for your blades, or individual saya (wooden sheaths) for each knife.

If you do store knives in a drawer, use individual blade guards and make sure the knives are not touching each other or other hard objects.

Avoid storing Japanese knives in knife rolls for extended periods unless the roll has individual pockets that hold each blade securely. Contact with other knives is one of the quickest ways to chip a fine edge.

Use it for what it is designed for

Japanese knives are precision cutting tools, not general-purpose kitchen implements. A few things to avoid:

• Do not use them on frozen food. The steel is hard but not flexible, and a frozen product can chip or crack the edge.
• Do not use the blade to scoop food off the board by pressing the flat of the blade down and dragging it. Use the spine, not the edge.
• Do not use a Japanese knife to cut through bone unless it is specifically a honesuki or deba designed for that purpose. A gyuto or santoku through bone is a good way to chip or crack the edge.
• Twisting or levering the blade while it is in contact with food puts lateral stress on thin steel that is not designed for it.

Sharpen on a whetstone

Japanese knives should be sharpened on a whetstone, not a honing rod and not a pull-through sharpener. Pull-through sharpeners remove far too much steel and leave a rough edge. Honing rods are designed for softer German steel and can chip the harder edge of a Japanese knife.

A basic two-stone setup - a medium grit around 1000 for sharpening and a finer stone around 3000-6000 for finishing - will cover most home cooks well. If you are maintaining a well-kept edge regularly, you may find you rarely need the 1000 grit stone at all.

Single-bevel knives like a yanagiba have their own sharpening requirements and are worth researching separately before attempting them for the first time.

If sharpening is not something you want to take on, a professional sharpening service a couple of times a year will keep most knives in good shape. Get in touch and we can point you in the right direction.

A note on carbon steel

Several Japanese knives, including some of the lines we stock, use carbon steel or a carbon steel core. Carbon steel takes a finer edge than stainless and many professional cooks prefer it, but it does require a bit more attention.

Carbon steel will react with acidic foods like citrus, onion, and tomato, which can cause discolouration. This is cosmetic rather than harmful, but if you prefer to avoid it, rinse and wipe the blade during use when cutting highly acidic ingredients.

As mentioned above, carbon steel will rust if left wet. If you do get surface rust, a light scrub with a cork and some water mixed with a small amount of baking soda will usually remove it without scratching the steel.

Over time, carbon steel develops a dark patina from use. This is a sign the knife is being used and cared for, and most cooks come to appreciate it.

Looking after a Japanese knife well is not complicated. Wash it by hand, dry it immediately, use a timber board, store it properly, and sharpen it on a stone. Do those five things consistently and a well-made knife will last you decades.

Browse our full range of Japanese knives at Chef & a Knife.