The Single Whip Law or the "Single Whip Reform" (simplified Chinese: 一条鞭法; traditional Chinese: 一條鞭法; pinyin: Yi Tiao Bian Fa) was a fiscal law first instituted during the middle Ming dynasty, in the early 16th century, and then promulgated throughout the empire in 1580 by Zhang Juzheng.
The measure aimed primarily to simplify the complex fiscal code under Ming law, by commuting most obligations towards the central government - from land and poll taxes to the labour obligations of the peasantry and the tributes of prefectural and county officials - into a single silver payment, at a level based on the population and cultivated land in each prefecture. Therefore, by reducing complexity, the Single Whip law reduced the costs of tax collection, while also increasing the tax base.
The unit of tax collection was changed from rice to silver, which led to an increase in the import of silver into China from Spain-controlled America and Japan. Because of the sheer amount of silver being imported into China, inflation occurred until the silver taxpaying system was no longer sustainable. The Single Whip Law led, in the long term, to the overthrow of the Ming dynasty, but it also increased European trade in the region.