The difference between Japanese knife and Western knife is that the way the knife is ground. Traditional Japanese knives are called Kataba bocho (single sided edge/blade)
that is having a bevel on only one side of the blade (if you are right handed, the bevel should be on your right when you hold a knife.) Hence, if you cut with a Japanese blade,
you will find it has a natural tendency to steer to the left. On the other hand, Western knives, Ryouba Bocho, have a bevel on both sides of the blade and so that the knife will
cut through food without steering. There are a number of different types of Japanese kitchen knives. The most commonly used types in the Japanese kitchen are:
the deba bocho (kitchen cleaver): This is used mostly cutting meat and seafood.
the santoku hocho (all-purpose utility knife) except frozen food.
the nakiri bocho and usuba hocho (Japanese vegetable knives)
the tako hiki and yanagi ba (sashimi slicers)
There are two classes of traditional Japanese knife forging methods.
Honyaki is true-forged knives, made from one material. This is generally a top-grade knife-specific steel (blue and white steel are most common). This is more likely to be
used by a professional chef or enthusiast in cooking.
Kasumi is made from two materials, like katana: high-carbon steel "hagane" (blue or white steel in good kasumi knives) and soft iron "jigane" forged together. This style of
knife offers a similar cutting edge to a honyaki blade in high-grade knives. It offers the benefit of being "more forgiving" and generally easier to be taken care of than the
honyaki style(because of its stiffness). Some see this as an advantage.
San Mai generally refers to knives with the hard steel hagane forming the blade's edge and the iron/stainless forming a lamination on both sides. In stainless versions, this
offers a practical and visible advantage of a superb cutting edge of modern Japanese knife steel with a rusting resistant exterior.
In professional Japanese kitchens, the edge is kept free of rusting because knives are generally sharpened on a daily basis. Rusting is also avoided for taste and aesthetic
reasons as well.
Honyaki and kasumi knives can be forged out of steel. Based on their duration of sharpness and hardness, however they are more difficult to use and maintain. Additionally, there are high-grade quality kasumi knives called hongasumi and layered-steel kasumi called Damascus that have longer kirenaga.
Originally, all Japanese kitchen knives were made from the same carbon steel as katana. More expensive san mai knives have a similar quality, containing an inner core
of hard and brittle carbon steel, with a thick layer of soft and more ductile steel sandwiched around the core so that the hard steel is exposed only at the cutting edge.
Nowadays stainless steel is often used for Japanese kitchen knives, and san mai laminated blade construction is used in more expensive blades to add corrosion
resistance while maintaining strength and durability.
Much high-quality Japanese cutlery originates from Sakai, the capital of samurai sword manufacturing since the 14th century. After the Meiji Restoration, the carrying of
swords by the samurai class was banned as part of an attempt to modernise Japan. Though demand for military swords remained and some swordsmiths still produced
traditional samurai swords as art, the majority of swordsmiths refocused their skill to cutlery production.
During the Edo period (1603–1867) (or more precisely the Genroku era (1688–1704)) the first deba bocho were manufactured, soon followed by a wide range of other styles.
Making kitchen knives and related products is still a major industry in Sakai, using a combination of modern machinery and traditional hand tools to make stain-resistant
carbon steel blades.
(a) and (c) only on one side, where (a) is for right-handed use and (c) is for left-handed use. (b) is angled on both sides, Unlike western knives, Japanese knives are often single ground, i.e., sharpened so that only one side holds the cutting edge. As shown in the image, some Japanese knives are angled from both sides, and others are angled only from one side, with the other side of the blade being flat. It was originally believed that a blade angled only on one side cuts better and makes cleaner cuts, though requiring more skill in its use than a blade with a double-beveled edge. Usually, the right hand side of the blade is angled, as most people use the knife with their right hand, with ratios ranging from 70–30 for the average chef's knife, to 90–10 for professional sushi chef knives; left-handed models are rare and must be specially ordered and custom made.
Professional Japanese chefs usually own their personal set of knive. Some professional chef even own two or three sets of knives, which they alternate every other day. After sharpening a carbon-steel knife in the evening after use, they normally lets the knife "rest" for a day to restore its patina and remove any metallic odour or taste that might otherwise be passed on to the food.
Japanese knives feature subtle variations on the chisel grind: firstly, the back side of the blade is often concave, to reduce drag and adhesion so the food separates more cleanly; this feature is known as urasuki. Secondly, the kanisaki deba, used for cutting crab and other shellfish, has the grind on the opposite side (left side angled for right-handed use), so that the meat is not cut when chopping the shell.