Under the tax collection system established in the Medieval period taxes relating to public duties and labor services, which were kinds of zoyaku (odd-jobs tasks), were assessed for myoden (rice field lots) as a collection unit; on the other hand, taxes relating to public duties and labor services were collected in regions where myoden had not sufficiently established or from people who did not belong to the ruling system of shoen (manor) and koryo (mainly non-cultivators) (mostly non-farmer), such as kugonin (groups of producer-merchants) or jinin (shrine dependents) by assessing for zaike as a collection unit.
中世において成立した収取体制においては、雑役系の公事・夫役は名田を収取単位として租税の賦課が行われていたが、名田が十分に確立されていない地域や供御人・神人など荘園・公領の支配体系に属しない人々（主に非農業民）から公事・夫役を収取するために在家を単位として賦課したのである。