How to Care for a Japanese Kitchen Knife: Washing, Drying, Rust and Storage
Researched. This guide compiles care instructions published by Japanese knife makers (KAI, Tojiro, Global, Jikko and Sakai Ichimonji Mitsuhide), checked on October 3, 2026. Where makers disagree, we say so. Always follow the instructions for your own knife first. This article contains no affiliate links.
Japanese knife makers publish detailed care instructions, and they do not always agree. Here is what the makers themselves say, side by side.
The short version
- Hand-wash and dry right away. Most makers advise against dishwashers.
- Stainless steel can rust too, so dry it the same way you would carbon steel.
- Do not twist the blade or cut bones and frozen food with a thin kitchen knife.
- Use a cutting board that is gentle on the edge, such as wood.
- Store it dry. Oil a carbon-steel knife you will not use for a while.
Dishwashers: what each maker says
| Maker | Dishwasher stance |
|---|---|
| KAI | Only all-stainless knives with integrated metal handles, or knives whose package says dishwasher-safe. Carbon-steel blades, clad blades with a carbon-steel core and wooden handles are not. |
| Global (Yoshikin) | Do not use, because it can lead to rust. |
| Tojiro | Not recommended. Detergent chemicals raise rust risk, and water pressure can knock the edge against other items. |
| Sakai Ichimonji Mitsuhide | Not recommended, except for some products. |
KAI’s own range shows why the package matters. In February 2014 it launched two Seki Magoroku lines, Moegi and Akane, with a stainless core and marketed them as dishwasher-safe. This does not apply to every Seki Magoroku knife.
How to wash
- Use a sponge and neutral dish detergent. Global says not to use steel wool or bleach.
- KAI suggests laying the knife flat on the cutting board to scrub each side. Sakai Ichimonji Mitsuhide suggests holding the sponge from the spine side, away from the edge.
- Jikko says to wash the knife right away after cutting acidic food such as tomato or lemon.
- Jikko also says to keep knives with wooden handles out of the sink and out of water.
Drying
KAI and Tojiro say to wipe the knife dry with a cloth immediately after washing. Sakai Ichimonji Mitsuhide names incomplete drying as a common cause of rust. Jikko says that for wooden handles, towelling off the water is the most important step.
Rust
Why stainless rusts too
Rust needs oxygen and moisture. Stainless steel resists rust thanks to a very thin chromium-rich surface film, but Sakai Ichimonji Mitsuhide explains that contact with other metals, especially rusty ones, can break it. Sakai Ichimonji Mitsuhide and Tojiro call this contact rust (moraisabi). KAI advises washing promptly after cutting salty or acidic food. Jikko says stainless knives need the same care as carbon steel.
Removing light rust
- KAI: rub with cleanser or a rust eraser. Deeper rust needs a whetstone, and advanced rust may not come out completely.
- Jikko: use cleanser with a soft sponge or a wine cork, or a rust eraser on the flat of the blade only, away from the edge. It warns that erasers can wear away Damascus patterns.
- Tojiro: for rust on the edge itself, do not scrub, because of the risk of injury; sharpen it out on a whetstone instead.
Sakai Ichimonji Mitsuhide advises treating rust early, before it goes deep.
Patina on carbon steel
Carbon-steel knives darken with use. Jikko says knives form a protective oxide film with use, so new knives rust more easily. Sakai Ichimonji Mitsuhide distinguishes stable black oxide, which protects the steel, from reddish-brown rust, which damages it.
Cutting habits that prevent chips
Sakai Ichimonji Mitsuhide gives this advice:
- Do not twist or pry the blade, for example when cutting a pumpkin. Thin blades are weak against sideways force.
- Do not scrape food across the board with the edge; turn the knife over and use the spine.
- Avoid frozen food and fish bones or shells. Use a knife designed for them.
Cutting boards
Makers agree that wood is gentle on the edge. They disagree on plastic: Global accepts soft plastic boards, while Sakai Ichimonji Mitsuhide says plastic is hard and damages edges.
Storage
- KAI says to store knives in a ventilated, low-humidity place, and Global says to store them somewhere well ventilated.
- For a carbon-steel knife you will not use for a while, makers suggest a thin coat of oil. They disagree on which: KAI and Jikko allow salad oil, but Sakai Ichimonji Mitsuhide recommends camellia oil and advises against salad oil, which it says turns sticky.
- Jikko says knives used every day do not need oiling.
Wooden handles
KAI says wooden handles must not go in a dishwasher or dish dryer and should not be bleached. Jikko says handle rot comes from habits, so keep the knife out of the sink and dry the handle straight away.
How often to sharpen
- KAI: on a whetstone, once or twice a month.
- Sakai Ichimonji Mitsuhide: ideally every one to two months for home use.
See our beginner’s guide to Japanese whetstones for how to choose a stone.
Sources
- KAI: knife FAQ (Japanese)
- KAI: care after use (Japanese)
- KAI: why knives rust (Japanese)
- KAI: dishwasher-safe Seki Magoroku launch (2014, Japanese)
- KAI: knife maintenance (Japanese)
- Global (Yoshikin): care (Japanese)
- Global (Yoshikin): column (Japanese)
- Tojiro: knife care (Japanese)
- Tojiro: cutting boards (Japanese)
- Sakai Ichimonji Mitsuhide: care and storage (Japanese)
- Sakai Ichimonji Mitsuhide: care points (Japanese)
- Sakai Ichimonji Mitsuhide: rust (Japanese)
- Sakai Ichimonji Mitsuhide: chips (Japanese)
- Sakai Ichimonji Mitsuhide: choosing a cutting board (Japanese)
- Sakai Ichimonji Mitsuhide: anti-rust storage (Japanese)
- Sakai Ichimonji Mitsuhide: rust removal (Japanese)
- Jikko: knife rust (Japanese)
- Jikko: removing rust (Japanese)
- Jikko: handle rot (Japanese)
We check facts against the sources above, as described in our Editorial & Accuracy Policy. If you spot an error, please tell us through our contact form.
