The Sadaijin (minister of the left) or, if absent, the Udaijin (minister of the right) assumed the head of the 'Jin' (the council), because the Sessho (regent) and the Kanpaku (chief adviser to the Emperor) served as assistant and deputy of the Emperor and did not participate in the Jin and Daijo-daijin (Grand minister of state) that was an honorary post.
摂政・関白は天皇の補佐・代理人の位置づけであるので陣には加わらず、太政大臣も名誉職であるので「陣」の筆頭は左大臣、出席していなければ右大臣となる。