The bevel of a knife is one of the most important aspects that help to define its sharpness, strength, durability, and use. To put it simply, a bevel is the ground angle and shape of the blade’s edge, and depending on what it’s made of and how it’s ground, it can dictate the type of knife you have. Traditionally, the Japanese have knives that fall into two categories of bevels: a double bevel, or a single bevel. It’s common to also hear this referred to as a doubled-edged blade or a single-edged blade.
A double-bevel knife, or double-edged blade, means that it has a bevel on both sides. These knives are the most common, especially in Western style knives like those of the French and German. However, the Japanese have many double-edged knives as well, such as the gyuto knife, the sujihiki knife, and the honesuki knife.
When talking about double-edged knives, you can mainly assume the angle of the blade on either side is in a 50-50 ratio, meaning that if one side has been ground to 11 degrees then the other side has also been ground to 11 degrees, and the total angle of the blade is 22 degrees. Asian knives typically have a slightly smaller angle than other traditional western knives, and both sides are sharpened to roughly 8 degrees, making them much sharper.
In the case of some knives, there is no angle on the other side of the blade. These knives are referred to as a single-edged blade. However, in practice, we have found that the vast majority of Asian knives sold in the United States are not single bevel, but rather traditional knives with a bevel on both sides. If you’re not sure, it is generally safe to assume that your knife has a bevel on both sides.
For most chef’s, using a single-bevel blade involves learning new knife skills and techniques. It may also mean custom ordering a blade if you are left handed, so that you can correctly use the knife. However, once able to use it correctly, a single-edged blade can make thinner cuts, especially with vegetables, which is great for sushi chefs.