Every puric was obliged to give a certain amount of work to the state. This tax-through-work service was called mit'a. Only the
state and religious officials were exempt. Each ayllu cultivated fields within its communally held lands for the Sun and the Inca,
that is, for religion and the state. The crops from these fields, planted and harvested communally, were stored for official use.
Another form of work service was prescribed for various projects: road building, bridge building, mining, and the erection of
temples, forts, and royal residences. All was under the supervision of professionals. Accurate records of work service for each
community were kept on a knotted string-- the quipu. In addition to work service, every puric formed part of an agrarian militia
and was liable to military service at any given moment. When he was absent on a military campaign other members of the ayllu
cultivated and harvested his allotment of land.