The katsuobushi kezuriki are designed to shave whole pieces of katsuobushi (a dried fish product made from bonito) into thin shavings. These shavings are used in a wide variety of ways in Japanese cuisine- as a topping for cooked foods, to add richness to sauces, making dashi, and so forth. The blade is removable and can be sharpened in the same manner as many wood planes.