A plane used to smooth the sides of a groove, particularly in a doorsill or lintel, after the base plane, *mizoganna 溝鉋, has been used to make the base of the groove. The groove sides are known as waki 脇. In order to pare both sides of the groove, the plane has wakiganna set for right-side cutting and others for left-side cutting. The shape of the cutting blade is very much like a knife. The blade is fixed into the top of the plane stock parallel to the mouth, and the shavings are ejected from a small opening in the opposite side of the sole.
Another grooving plane, the small *hibukuraganna 樋部倉鉋, has a slim base with virtually no flat surface. The wakiganna, however, has a flat base area, which allows the plane to be applied more firmly to the timber when paring.