Sanze-isshin Law (a law allowing farmers who cleared new lands to own them for a period of three gen (三世一身法)

Sanze-isshin Law (sanze isshin no ho) is kyaku (amended laws of Ritsuryo codes) which was issued on May 29, 723 during the early Nara period, and the law which allowed a land cultivator to own his land privately for three generations (or only for his own generation) in order to encourage to cultivate rice fields. In those days it was also called Yoro Seven Kyaku.

Main contents of the law

It says that when a man cultivates new rice fields by building new irrigation facilities (ditches or ponds), he is allowed to own the land for three generations (the person himself - his children - grandchildren, or his children – grandchildren - great grandchildren); when he cultivates new rice fields by using existing irrigation facilities (when he repairs old ditches or ponds and makes them usable), he is allowed to own the land for his own generation.

Background of enforcement of the law

On June 17 in the previous year of the enforcement of the Sanze-isshin Law, there was a project for a million hectares of land cultivation among the policies which Dajokan (Grand Council of State) had reported to the throne and was approved. This was such an enormous project which aimed to newly cultivate a million hectares of agricultural land for increasing food supply (Even the total fields in those days had not reached one million hectares).

Reasons this project was approved are considered as follows but none of them is definite: As population increased, shortage of food supply occurred; financial demand for national defense in remote regions occurred (in this theory some say enforced areas of the project were limited to remote regions such as Mutsu Province); it was a project to show off the power of Prince Nagaya (Nagaya no Okimi); and so on.

Anyway the Sanze-isshin Law is thought to be enforced to carry out this project.

Effect of enforcement of the law

It is almost certain that enforcement of the Sanze-isshin Law contributed to the increase of new rice fields. But its effect seems to have lasted only temporarily. In the Konden Einen Shizai Law (the law permitting permanent ownership of newly cultivated land) which was enforced 20 years after the Sanze-isshin Law (in 743), it says, 'Although there is the Sanze-isshin Law, farmers do not cultivate land because of idleness as the land is confiscated when the time limit comes,' so it seems that the effect of the Sanze-isshin Law lasted merely less than 20 years.

However, it is impossible to think that three generations pass only for 20 years and the time limit for confiscation comes close. It is also possible to think that it was a mere excuse that farmers were idle and it was influence peddling for large temples and local ruling families to enlarge their private properties.

Positioning in the Ritsuryo system

Generally the Sanze-isshin law is considered to be the first step for collapse of the Kochi-komin Sei (a system of complete state ownership of land and citizens) which is a basis of the Ritsuryo system, along with the later Konden Einen Shizai Law.

However, there is no description in the Ritsuryo codes that the Kochi-komin Sei is the basis of the Ritsuryo system.
(It can be seen that it was only advocated by Marxist historians in the Showa period.)

Also there is a theory that the very fact that enforcement of the Handen Shuju Ho (the law of periodic reallocations of rice land) could not be carried out after the Heian period had more effect on the collapse of the Kochi-komin Sei, or that the Kochi-komin Sei was not thoroughly carried out from the beginning.

It is considered that the Sanze-isshin Law was established as a special measure especially to urge cultivation of rice fields because there were no regulations concerning the cultivation in the Denryo (the law about providing rice fields) of the existing Yoro Ritsuryo code. From this point of view, the Sanze-isshin Law can be said to be the law to complement loopholes of the Ritsuryo codes.