Japanese style knives are made of very hard steel (60+ HRC hardness). This allows the blade to be very thin, which ensures long-lasting, fine sharpness. That's why Japanese knives are also lighter in weight than other knives, but they are more sensitive than cheaper knives made of softer steels. The high hardness of 60+ HRC makes the Japanese knives more brittle. Think of a Japanese knife as buying a nice supercar. You won't drive your new Ferrari off-road. Japanese knife is a high performance tool, treat it with respect.
When it comes to the angle of a knife, the lower the angle, the sharper the blade. While Western blades have a larger angle (20-25°) and therefore a thicker edge, Japanese knives have much thinner angles (15-20°) for a sharper edge which means more care needs to be taken when sharpening these fine angle knives.
They will dull as they might rub against other things like forks, spoons etc., and the chemicals in the detergent are very strong and can react with the steel creating pits or discoloration. It will also kill the wood handle in a very short time. The use of the dishwasher voids any guarantees with most all knifemakers.
Never leave the knife in the kitchen sink. Leaving a dirty, wet knife in the sink for a long period of time will damage the blade. This especially applies to better knives marked as 'stainless'. They are not completely stainless, they are only corrosion-resistant to a certain level. Spending a night in the sink can have sad results. It is also extremely dangerous to to leave sharp knives in the sink where you will maybee later put down your hands.
A DISHWASHER CAN KILL A KNIFE IN A FEW YEARS,
BUT WITH KNIFE CARE IT CAN LAST A LIFETIME.
2. ALWAYS HAND WASH THE KNIFE.
Handwash the knife and clean it gently right away after use with soap and water or just hot water.
We suggest to occasionally clean the knife with a cloth during use. Working with a clean knife is easier and safer.
A dull knife will require more pressure to get through your food. More pressure means a higher chance of slipping and accidentally cutting yourself. More pressure also means that any accidents are likely to be much worse than the small nick you'd get from a sharp knife that's used gently. Buy and learn how to use a honing steel and make sure you keep your knives sharp at all times, for utility and safety.
Sharpening is a bit more complicated, but not impossible if you've got a bit of patience, or you can get it done by a professional. If you hone your knife often, you won’t even have to sharpen them more than once a year.
4. ALWAYS USE A CUTTING BOARD.
End cut wood boards are the best, or a professional synthetic board. Never cut on a marble countertop, glass plate, ceramic baking tray, steel tray and other similar surfaces which were not designed for cutting.
When we cut vegetables on a cutting board we usually scrape the pieces off the board and into the pot using the blade of the kitchen knife. The sharp edge of the blade is only a few microns thick and is designed to resist vertical pressure relatively well. In case of scraping, the force is applied transversely on the board which is harmful to the blade. To scrape the vegetables off the cutting board simply turn the blade around and use the spine of the knife instead.
6. STORE YOUR KNIFE WITH CARE.
Kitchen knives are not supposed to be stored in drawers together with your cutlery and other kitchen utensils. Moving around and rubbing against other utensils inside the drawer will damage the delicate blade and a great way to get nicks and dings on it. It is also dangerous since you can get cut while going through the drawer looking for something.
Always store your knives in a knife block or on a magnetic knife board. There are also knife blocks for drawers. If you have children around and want to keep the sharp knife/knives in a closed drawer for safety, many Japanese knives sometime have a wooden saya for blade protection included. You can also buy a synthetic protective saya that stay on the blade in the drawer for $5.00-8.00.
A sharp knife cuts better, therefore you will not need much force for cutting. For certain ingredients, the weight of the blade is almost enough, others require some minimum pressure. When applying less force we damage food ingredients less, we tend to be more precise reducing the likelihood of getting cut. When the knife cuts off a piece of a food ingredient it strikes the cutting board. These strikes also influence the sharpness of the blade.
8. NEVER CUT BONES OR FROZEN FOOD.
If you use the Japanese knife for preparing poultry and meat, cutting into bones can result in edge chipping. Use a more suitable knife for this purpose. If you accidently drop the the knife chipping can also occur.
9. NEVER TWIST THE BLADE WHEN YOU CUT.
Chipping can occur.
