In the last few centuries of the imperial age, tenant farmers obtained a right to continue the tenancy contract over generations (yongdian zhi 永佃制 "system of eternal tenancy") and even if the landowner sold the ground. Chinese law discerned between the right of ownership (tiandi quan 田底權) and the right of use (tianmian quan 田面權). While the former was in the hands of the landlord, the latter remained in the hands of the tenant, in other words, there was a legal difference between the "ground of the field" (tiandi 田底, tiangu 田骨, liangtian 糧田, datian 大田, mintian 民田, zhengtian 正田, damai 大買, daye 大業, damiao 大苗, xiapitian 下皮田, lizi 里子) and the "surface of the field" (tianmian 田面, tianpi 田皮, zhitian 質田, xiaotian 小田, ketian 客田, shaotian 紹田, xiaomai 小買, xiaoye 小業, xiaomiao 小苗, shangpitian 上皮田, mianzi 面子).
In the full long-term tenancy system, the landlord had only the right to obtain a rent more or less adapted to the average harvest (see quota-rent system and fix-rent system) from which he had to pay the land tax (depending on local custom, the tenant might take over part or the whole of tax payment), and not the right to take away the right of use, arbitrarily raise the rent or to interfere into the economic activities of the tenant farmers. The tenant farmer in contrast had the right to withdraw from the contract, to sublease land, and even to pawn the rights of use. All these activities from the tenant's side could not influence the contract with the landowner, just as the change of ownership could not influence the right of use. There were also tenancy models, in which the tenant farmer had the right of long-term use, but not the privilege to sublease or mortgage the right of use.
The right of "eternal use" emerged during the Song period 宋 (960-1279) or even somewhat earlier and won dominance over tenancy contracts during the Ming 明 (1368-1644) and Qing 清 (1644-1911) periods. In this time, most tenancy contracts of this type originated in fields that had been created by clearing land or ameliorating old fields. In late imperial times, most long-term contracts were the result of indebtedness, because of which free farmers had to sell their ground, but were allowed to stay and use it.
Long-term use was very widespread in the southern and eastern provinces of China, where most tenancy contracts were concluded between private persons, while fields in north China were subject to different ownership systems like Banner fields (qidi 旗地) and public fields (guantian 官田). In the 19th century, the number of long-term tenancy contracts declined.
Even if long-term contracts provided tenant farmers a safe background to plan for their economic activities and their lives, the height of the rent or the landowner's request of a rent security (yazu 押租) posed heavy financial burdens on the farmers' shoulders. Many of them had to mortgage the right of use, mostly in favour to the landowner, who eventually (if the farmer was not able to pay back the loan) acquired the right of use, and not just the right of ownership. Such situations created complex legal situations, in which one field might be "owned by two" or many persons (yi tian er zhu 一田二主, in case of sublease), if a third-party creditor was involved (yi tian duo zhu 一田多主). Alternatively, a landowner might simply purchase the right of using the soil, or acquire it for outstanding rent.