Boning Knives Boning knives are a special type of kitchen knife that typically have several design features that help with boning meat, fish, and poultry. Boning knives usually have a narrow blade, sometimes flexible but some prefer stiff. They also have slender and sharp points. The typical size of a boning knife is 12 cm to 17 cm or about 5 to 6 ½ in length on the blade. Japanese boning knives are called Honesuki or Gukojo.