Japanese knives usually use one of two possible forging techniques, named Honyaki and Kasumi. Honyaki is called “White Steel” for it’s high carbon steel blade, and is made from one type of metal. Kasumi is made by forging steel and soft iron together. The steel in the knife comprises the blade’s edge, and the soft iron comprises the blade’s spine and body. These two techniques are both legendary in their own right.
There are literally dozens of different types of Japanese knives. The most popular of these knives is the Deba, or heavy cleaver, the Santoku, a utility knife, and a vegetable knife called the usuba. There are dozens of other types of knife, made for working specifically with eel or tuna or octopus. With so many offerings of style, most chefs just find one or two that they like best and they will user primarily these knives. One of these knives is likely to be a Santoku, which is legendary worldwide as the most versatile knife in the world.