One thing that makes traditional Japanese knives different from western knives is the fact that many types are honed only on one side; the right side. For a left handed person, they would have to special order the knife honed on the left side.
This single sided honing allows one to create the sharpest edge possible on a sushi knife. Much sharper than can be accomplished with a traditional western style knife which is honed equally on both sides and are known as double-edged knives.
If you are just starting out, whether at home or at work, knowing which sushi knife you will need or what each is used for can be confusing.
The Two Main Types of Japanese Sushi Knives
There are 2 main groups of Japanese knives and they are divided based on how they are honed.
A traditional sushi knife is honed on one side and a Japanese western-style sushi knife is honed on both sides (double-edged) and is based on western knife design but with a Japanese influence.
The main Japanese influence is that instead of being ground 50:50 (or like a "V") typical of standard western knives, they are ground to a thinner asymmetrical edge with ratio's like 70:30, 60:40 and 90:10.
See image 70:30 below for an example of the Japanese version of the western blade edge compared to a standard 50:50 edge. 70:30 seems to be the most common.
So now that you know the main difference between the two let's look at the most common styles in each group.
Traditional Knives typically used in making Sushi
1. Deba-bocho. A heavy duty cleaver used for tough jobs like cutting through the bones and cartilage of fish. In the pictures above, the deba is the one on the bottom.
2. Usuba-bocho/Kamagata Usuba-Bocho and Nakiri-Bocho (Western style). A vegetable knife used for peeling, slicing and chopping. The Usuba-bocho is the one on top in the pictures above.
3. Yanagiba or Sashimi-bocho. A sashimi knife used to slice up raw block of fish and fish fillets. The Yanagiba is the long slender one in the middle.
Let's go over each one individually.
The Deba is a small, curved Japanese carving knife that is designed to remove the heads from and then fillet the fish. It could almost be best described as a cross between a meat cleaver and a chef's knife.
They come in varying sizes starting from 4 inches all the way up to 12 inches long. The blades on these knives are normally thick, strong and beveled on one side and is designed with a more obtuse angle on the back of the heel making it ideal for the hard work of removing the heads off of fish. The remainder of the blade is then used to lay against the bones of the fish to remove the fillet.
This sushi knife is not really a required item for a home sushi chef. It is mainly used by professional sushi chefs who spend a part of their long day preparing whole fish for sushi.
In most cases at home you will probably obtain your fish in blocks and most likely frozen, so the need to remove the head and fillet a fish is unlikely. On occasion when the need does come up, the standard chef's knife that you probably already have at home should work just fine as long as it is sharp.
The Ususba knife is a Japanese-style vegetable knife with a thin, straight blade edge that is sharpened on the right side. This sharpening on one side is known as Kataba.
Better quality Usuba knives have a slight depression on the flat side of the blade. This Usuba Kataba style sushi knife (flat, thin, blade sharpened on one side with depression on the flat side) makes it possible to cut thinner slices than is possible with a double edged blade (also called ryoba) although the ryoba style makes it easier to make straight cuts. It also takes more skill to properly use a Kataba style Usuba sushi knife.
There are many terms used to describe these usuba knives so let's try to take is slow and hopefully make understanding the differences clearer.
All of these knives are Usuba knives and actually usuba means "thin blade". They are normally used by professional Japanese chefs. The picture on the right above is what you could call a standard usuba knife. It has a square blunt edge on the front that is most popular in the Kanto region of Japan or more easily recognized as the area around Tokyo.
Kamagata Usuba Knives
The Kamagata usuba variation is more popular in the Osaka region and features a spine that slowly drops down to the edge of the tip. The picture above on the left is an example of this style. This tip is used to make intricate cuts and designs in vegetables.
The Usuba sushi knife in general is most popularly used for chopping and slicing razor thin sheets off of vegetables for Katsuomuki.
Nakiri Bocho (Japanese Western-style knife)
Now, the Nakiri sushi knife is also available in the same "styles" (blunt front end and curving front end) as mentioned above, but the difference is that it is designed more for home use because of its double-edged blade (called Ryoba).
The ryoba style is easier to master and is easier to make straight cuts with making it more appropriate for home use. It also usually has a black blade.
If you must have one of these Usuba knives to slice and chop your vegetables, just know the differences explained above and you'll be able to pick out just what you want.
For all intent and purposes however, you could get by with a good, sharp standard chef's knife but to really enjoy the entire sushi making experience at home it is nice to have these authentic sushi chef knives available.
In Japan, preparing sushi and sashimi is very serious business. One of the most important requirements is that sliced meat be smooth, shiny and sharp when viewed through a microscope. This kind of precision can only be accomplished with a special knife like a Yanagiba.
The Yanagiba is a long, very thin, single beveled (usually on the right side) sushi knife used in preparing sashimi and sushi. Left hand versions can be obtained that are beveled on the left side, but they are very expensive.
This kind of knife is specially designed to be pulled in one direction, the goal of which is to sever the cut in one swift motion beginning at the heel of the knife and ending at the tip. No pushing action is recommended as this would ruin the smoothly cut surface of the meat and probably tear it.
The thinness of the blade allows the knife to be pulled with very little force which aids in the cutting action. Higher quality knives have a slight depression on the back (or flat) side to keep the piece from sticking, allowing it to be removed easily.
The length of these knives varies from 8 to 12 inches and there is no "best" size. Mostly its a matter of personal preference. Just know that the longer the knife is, the harder it is to use for most people.
WHAT TYPE OF STEEL IS BEST
The first is carbon steel. This type of steel gives the sharpest edge possible but requires the most maintenance and can rust. So if you buy a sushi knife made of carbon steel, you will be sharpening it more often than other types of steel and you'll also have to be very diligent in keeping the blade washed and completely dried.
The second choice is stainless steel. Stainless steel does not rust but it also does not hold as sharp an edge as carbon steel or composite steel.
And last but not least are the composite steel knives that hold a sharper edge than stainless steel and are less susceptible to rust but can be quite costly.
So which do you Choose?
Which one you choose will come down to personal preference.
If you have to have the sharpest possible sushi knife available, then choose carbon steel. Just be ready to keep it sharpened and well cleaned and dried after each use. If stored for an extended period of time, you should put vegetable oil on the blade and wrap it in a newspaper.
If you want a low maintenance sushi knife that is not going to rust and you don't care if yours is not the sharpest sushi knife in town, then stainless steel may be the best option for you.
And if money is not an object, and you want some of the benefits of stainless steel but the ability to sharpen the blade to a higher degree then one of the composite steel knives may be worth looking into.