A smoothing plane. The hiraganna is used for smoothly planing the surface of a board or pillar. Of the many types of planes *kanna 鉋, it is the most frequently used. There are various types of smoothing planes, graded according to their use from the preliminary roughing plane to the special finishing plane. The series of hiraganna is used in order, beginning with the preliminary roughing plane, oni-arashikō ganna 鬼荒仕工鉋, used to cut away major surface irregularities, then the general roughing plane *arashikō ganna 荒仕工鉋 and the muratori kanna むらとり鉋. The finishing planes are the *chūshikō ganna 中仕工鉋, the *jōshikō ganna 上仕工鉋, and the *shiage ganna 仕上鉋. The planes used are selected according to the condition of the wood surface, but generally the three stages of general roughing, finishing, and special finishing are sufficient. For example, timber planed with the jōshikō ganna and the shiage ganna is glossy with a very fine surface quality. Apart from the preliminary roughing plane, all hiraganna use a double blade, nimaiba 二枚刃, and are therefore known as a joint plane, awaseganna 合せ鉋. Two blades are used because this pares the timber against the grain.
