After the Heian period, yonin system (remote appointments), which kokushi did not reside in his appointed province but his deputy attended the governance of the province on his behalf, was established, and it became popular for kokushi who adopted this system to set up the deputy post called mokudai (deputy kokushi) in kokufu (provincial office).
平安時代以降、国司自ら着任することなく国府の政務を代行を遙任された遙任という制度が確立し、遙任をした国司より国府に目代という地位が置かれることが一般的となった。