宋代"典需離業"的規定表明了典之本原,但其派生的權益及其多樣化表現卻引發歧義。譬如承典人將土地租佃給出典人,在宋代不被認可;而清代這種形式廣為流行,卻又在表象上造成"租息相抵"的錯覺。承典人可選擇典田的經營收益、投資收益,或變現未來收益,突出反映了田主、典主、佃農三者依托市場交易構筑的共享地權格局。典權不是使用權,也不是所有權,而是一種限定性物權形態的財產權,與抵押也有明顯的區別。典權的時代性差異在政府規定上得到相應的反映,宋代典田需要赴官辦理合同契,并過割田賦和納交易稅;清代中后期則免除了交易稅,無需過割田賦,契約形制上多采用單契,使轉典等相關后續交易更為便利。凡此階段性差異與特征,揭示了在典權發育過程中,交易規則與社會認識也經歷了曲折的演變,縱貫比較有助于把握典權之本原與多樣化形態,也有助于更全面地理解傳統中國的土地產權與交易形態。

The Song dynasty regulation that"mortgagors must leave their properties"(dian xu li ye)indicates the principle underlying mortgaging,but the diversification of its derivative rights and interests led to some ambiguity.For example,in the Song dynasty,the practice of the mortgagee renting the property in question to the mortgagor was not approved,but in the Qing dynasty,the practice was widespread,giving rise to the mistaken apprehension that"rent and interest cancel each other out."The fact that the mortgagee could choose whether to make a profit from operating the land,investing in it,or realizing future earnings shows that land owners,mortgagees,and tenants could build shared land rights based on market transactions.The differences in the content of mortgage rights at different times are reflected in government regulations.In the Song dynasty,someone mortgaging agricultural land had to go to an official to get a formal contract(hetongqi),settle the land tax,and pay a transaction charge.In the mid-and late Qing,the government remitted the transaction tax and ceased to require the land tax settlement process;the contract generally took the form of a single land title,making it easier to mortgage agricultural land.The distinctive features of all these processes show that as mortgage rights developed,the rules for transactions and their recognition by society underwent a complex process of change.Historical comparisons can help us grasp the principles and diverse forms of mortgage rights and give us a more comprehensive picture of traditional China’s land rights and transaction forms.