oni-arashikō ganna 鬼荒仕工鉋

A preliminary roughing plane. The oni-arashiko ganna has only a single cutting blade, expressed as ichimaiganna 一枚鉋, unlike most other planes, for example the *arashikō ganna 荒仕工鉋, *chūshikō ganna 中仕工鉋, and *jōshikō ganna 上仕工鉋, which have two blades. The oni-arashikō ganna is used to roughly plane timber and flatten the surface before going on to use other finer planes. Consequently a large quantity of thick shavings are produced through the wide mouth. Another feature of the oni-arashikō ganna is that the central part of the blade-edge expands slightly in a convex curve. This is because one can reduce the force used without losing stability, and with repeated paring the projections in the wood can be smoothed rapidly.