noun
wooden plane with a convex base curved both along and across the blade
Specialized woodworking tool used for shaping concave surfaces; the base is curved in two directions. Compare with 反台鉋, which is curved only along the blade direction.
See also: 反台鉋
職人は四方反鉋で曲面を仕上げた。
The craftsman finished the curved surface with a shihōsori-kanna.
反台鉋 has a convex base curved only along the cutting direction, while 四方反鉋 is curved both along and across the blade, allowing more complex concave shaping.
Compound of 四方 (shihō, 'four directions') + 反り (sori, 'curvature') + 鉋 (kanna, 'plane'), referring to the plane's curved base in two axes.