Although 'Kuchi' (literally meaning a mouth) --a word that refers to the entrances of Kyoto--seems to have been used to refer to the entrance in the late Kamakura period, we can see their descriptions in historical records of the subsequent Muromachi period as a seki (choking station); during the Muromachi period authorative organizations such as the bakufu (Japanese feudal government headed by a shogun), temples, and the Imperial court (or nobles) started to establish checking stations called 'Nanakuchi no seki' at the entrances to Kyoto and other locations to levy travelers sekisen (tolls).
京の出入口を表す言葉としての「口」は、鎌倉時代後半から使われていたようであるが、室町時代になるとその出入口をはじめとして、幕府、寺社、朝廷（公家）などさまざまな主体が「七口の関」と称される関（関所）を設け関銭（通行料）を徴収するようになったため、記録に関として「口」がみられるようになる。