It is said that kurodo with the longest tenure, in other words gokuro, was ennobled every year with the exception of the cases where the kurodo was allowed to remain in office (joryu), and that most of them made the transition to kokushi (provincial governors).
年労第一の蔵人即ち極臈が毎年叙爵に預かったとされ、叙留即ち留任の例外を除き、大概は国司に転じたという。