The labour recruitment law (muyifa 募役法), also called guyifa 雇役法 "Law on hiring labourers", or mianyifa 免役法 "Law on the avoidance of corvée labour" (see yaoyi 徭役) was part of the set of economic reforms carried out under the counsellorship of Wang Anshi 王安石 during the Northern Song period 北宋 (960-1126). It targeted at the replacement of obligatory labour service for official projects, which was part of the tax system, by hiring people on the labour market to carry out work for infrastructural projects like dykes, dams, roads, and so on. The law was launched in 1069 and three years later extended to the whole Northern Song empire.
Each prefecture was to calculate carefully in advance the funds needed for official projects. The necessary funds would then be allotted and to be spent for paying and feeding (called luqian 祿錢 or gongshiqian 工食錢) the workers. In addition to these expenses, the government would pay a premium of 20 per sent, called mianyi kuansheng qian 免役寬剩錢 "surplus extension funds for labour recruitment" and designed for use in years of crop failures as a replacement for the then cancelled substitutional pay for the labour corvée (the labour duty could be delivered in service, but with the increasing monetization of the Song economy, it was transformed into a payment, when labour was not needed). Effectively, the full transformation of labour service to the government into a monetary payment increased the tax revenue.
The new law changed the exemption of some households from the labour duty (officials, state employees [xingshi hu 形勢戶], landowners, females living alone, under-age males, and clerics) and required that these persons, too, paid the mianyiqian 免役錢, daiyiqian 代役錢, guyiqian 雇役錢 or zhuyi qian 助役錢 for the hiring of personnel working at official projects. There were thus many persons arguing against the new law, and trying everything to have it abolished, which happened in 1086, yet it was in practice only discontinued with the foundation of the Southern Song dynasty 南宋 (1127-1279).