Entering the Courtiers' Hall in the Imperial Palace' means entering the Courtiers' Hall called Tenjo No Ma in the emperor's private living quarters, i.e., in the south side of the emperor's residence Seiryoden; and during the Heian period, court officials were authorized by imperial sanction to enter the Hall without regard for their family rank and court rank.
昇殿とは天皇の日常生活の場である清涼殿南廂にある殿上へ昇ることで、平安時代は家格・官位に関係なく、廷臣ごとに勅許を得ることでこれを許されていた。