An explanation from eastredgallery.com: "The vast amount of irrigation projects launched during the Great Leap Forward required replacing traditional agricultural tools such as shoulder poles with carts and wheelbarrows. These needed ball bearings to operate most efficiently, which the worker in this poster can be seen producing. The hard alloy balls have to be machined extremely precisely, and their manufacture is beyond the skills of an average workshop. Workers throughout the country were encouraged through various channels to participate in the 'bearingification' drive, although the results of their labors would often have been unusable."