This is a farming tool used to pick out impurities after threshing crops. Its name varies by region, and includes winnower, air furnace, windmill, punggi, hand pinwheel, pinwheel, fan, vane, pungseon, seoncha, or punggo. It is a primitive form of machinery that raises wind to blow away empty heads, bran, or dirt mixed in the grains. Its form differs by region: one consisting of a support, a pillar, three to four blades fitted onto the pillar, and a handle for turning the blades to raise wind; one designed to raise wind using a wheel fitted with multiple blades attached within a large, round container; and one that has a wheel with multiple feathers inside a large, drum-like container with a large ventilation hole on each side. Winnows and sifts were widely used as farming tools for winnowing crops. While winnows and sifts are operated by hand, the winnowing fan utilizes wind, thus demonstrating higher efficiency than a winnow or a sift, despite its rudimentary mechanism.