This long and thin knife is, because of its characteristics, the typical example of the 'sashimi bocho' (Japanese: sashimi [raw fish] bocho [knife]) and it is used in Japanese cuisine to prepare sashimi and nigiri sushi. Each characteristic of this knife has its purpose. The long blade allows the user to cut a block of flesh in a single stroke, which prevents zigzag cutting and the creation of a serrated cross-section. The thinness of the blade is by these knives very important too. The blade is very thin behind the edge which allows the cut to be made using primarily the weight of the knife. Greater force or thickness would result in tearing or bruising of the flesh. While almost all western knives are used to push and cut, the yanagi ba is used to pull and cut instead. When preparing sashimi and nigiri sushi, the goal is usually to have cut surfaces that are smooth, shiny, and even in order to maximize the taste. The construction of the yanagi ba is designed for this purpose.
The Japanese named this knife 'Yanagi-ba bocho' (literally willow blade knife) because its shape is reminiscent of the long and pliant characteristics of a willow branch.
The blade is constructed from soft iron, which allows general toughness of the blade and ease of sharpening, laminated to high carbon steel, which allows hardness of the cutting edge and sharpness. The steel is typically Hitachi blue or white steel.
Yanagibas are typically made in 195-360 mm of length.