How to take care of your Japanese kitchen knives?

We often make the mistake of thinking that the more expensive a kitchen knife is, the more solid it will be. However, the reality is often the opposite; the more "high-end" a knife is, the more brittle it is, and thus, the more maintenance it will demand. This might sound a bit illogical, but to be fair, the same logic applies in other industries: cars, fabrics, and even with pens!

A low-cost knife usually has a thick blade made of a soft steel that is resistant to strokes. Sure, that type of blade is very unlikely to break, but its cutting edge is of such low quality that you'll need to hone it rather frequently.

On the contrary, a high-end knife such a good Japanese knife is usally equipped with a thin blade made of a highly hard steel. Why? Because a blade like that is able to have a much better cutting edge that will remain sharp for a long time. Cutting with such type of blade is just a remarkable pleasure.

However, such outstanding cutting performance comes at the expense of two "inconvenient" characteristics: a more fragile cutting edge, and a weaker resistance to oxydation because most Japanese steels contain a high pourcentage of carbon.

What should NOT be cut with a Japanese knife?

As an overall rule, Japanese knives do not like hard foods or anything that could make their blades twist. Here are some examples:

1. If you want to cut a butternut squash, a potimarron, or any other ultra hard vegetable, you should not use a Japanese knife. These vegetables are widely used in winter for making delicious soups, but you should always keep in mind that they are never to be handled with Japanese knives. If you decide to go against this statement, the risk of your blade's edge breaking is quite high.

Our suggestion: Use a vegetable peeler to remove the skin (instead of using a knife), and then use a chef knife or a santoku knife with a thick blade to cut it into pieces. This way there will be no broken blades!

Indeed, if you use a knife with a thin blade, or a blade made of a super hard steel, it is very likely that the edge will get damaged during the cut of such type of vegetable because even the minimum twist can cause a break. This type of damage can usually be repaired, but you'll end up losing several millimeters of the blade's height, which is the equivalent of several years of sharpening.

2. Every cut in which the blade gets in contact with a bone (regardless of whether it is a meat bone or a fish bone) should be avoided. 

Our suggestion: Prepare your piece of meat or fish by removing the bones with a basic kitchen knife, a boning knife, or a filleting knife. Then, you can use the Japanese knife for doing the rest of cuts.

3. All cuts on frozen foods are strictly forbidden. The hard blade of your Japanese knife will not resist well the hardness of the frozen ingredient.

Our suggestion: Use a special knife designed specifically for frozen foods, or use a thick blade of an old knife that you do not use that much anymore.

4. Be careful with hard cheeses: when you try to cut them, you must by all means avoid to twist the blade from left to right when trying to penetrate all the way down because this is a huge mistake. You should always cut that type of cheese inserting first the front of the blade pushing straightly until the back penetrates the cheese at last. Another  (and wiser) option could be to simply use a cheese knife.

In conclusion, Japanese knives should be used to work with all the other types of vegetables, and boneless meats and fish. To be fair, that covers in fact most of the daily cuts that a cook has to do for the preparation of his or her recipes.

What type of cutting board should be used?

We advise you to opt for a wooden cutting board or one made of plastic. With these types of boards, the edge of your knife's blade will be preserved as these materials are "soft" enough.

On the contrary, you must absolutely avoid using cutting boards made of glass and all other types of "hard" surfaces such as marble. These materials will definitely damage the cutting edge of your knives, and they might even break it if you make a cut that is just a bit too strong.

How to clean your Japanese knives?

We'll go straight to the point: washing in the dishwasher is forbidden. Just don't. Every Japanese knife must be washed by hand using a bit of mild detergent, and it must be wiped immediately afterwards with a soft cloth. Even if the blade is made of "stainless" steel, rust spots are likely to appear on the knife if it is left to dry by itself. In fact, quite often, when the outer layer of the blade is made of stainless steel, the blade's core has a very high level of carbon content, which explains why the blade is so prone to suffer from oxydation.

The Japanese knives with blades that have an outer protection layer of stainless steel could in fact be the least resistant to corrosion. They can be compared to knives made of carbol steel or knives with an outer layer of iron. For these knives, it is completely normal for the the blade to start changing its colour after the very first usage. This is inevitable even if you take good care of the knife. Some traces might appear on the blade with the pass of the days, and that would be entirely fine (the traces could be caused, for example, by the acids of the foods being cut). This is why carbon steel knives are recommended for connoiseurs that are perfectly aware of the characteristics of this material. We remind you that there are no health risks if you use a blade with rust spots. 

You can also grease the blade of your Japanese knife with mineral oil once in a while to protect it from oxydation (especially if you do not use the knife everyday).

We recommend you to store you knife in a dry place entirely free of humidity.

If the handle of the knife is made of wood, you must avoid to wet it because wood can absorb the water, which can then cause the wood to move and create some cracks on the surface.

Finally, if despite practicing all the tips given on this page some traces appear on the blade, we insist that this does not represent any health risk. The blade would perhaps be less aesthetic, but it can perfectly continue to be used. You can also read our article on how to remove the rust spots from your blade by clicking here!

How to sharpen a Japanese knife?

A Japanese knife is different from a typical Wester kitchen knife, because it has an acuter sharpening angle and a harder steel. In general, the sharpening angle of a Japanese knife is of 15° on each side (30° in total), whereas for a Western knife the angle is usually between 18° and 20° (meaning 36° or 40° in total).

You can use a sharpening steel to hone the edge of your Japanese blade. All you need to do is to adapt the angle according to the knife. However, you must know that despite its name, a sharpening steel is used to hone a blade and not to sharpen it. If your blade is dull, a sharpening steel is useless.

We highly discourage the use of manual or electric sharpeners on any Japanese knife, because they often have a big sharpening angle and they remove too much material in every sharpening session. In other words, using one of these sharpeners will considerably reduce the lifespan of your Japanese knives.

The sharpening stone (also known as whetstone) is undoubtedly the most recommended accessory for sharpening not only Japanese but any other type of kitchen knife. There are several reasons that explain why whetstones are the ideal sharpening accessories:

- If you do your sharpening on a whetstone, the cutting edge will easily remain sharp for several months.

- A sharpening stone can also be used for repairing a blade: a break on the edge or a bent tip.

- The whetstones enable you to obtain a truly razor sharp edge that you cannot get with other types of sharpening accessories.

If you do not know which sharpening stone you should choose for your knives, we invite you to read our article on how to choose the right whetstone.

Discover the wide variety of Japanese kitchen knives available here on our website: