In addition, the Zao Mountain Range, a member of the one hundred biggest mountains of Japan, which lie on the border between Yamagata Prefecture and Miyagi Prefecture, has been the subject of mountain worship from ancient times so that mountaineering ascetics who believed in Shinto-Buddhist amalgamation of Kukai, came to practice ascetic training around the middle of the Heian period.
なお、山形県と宮城県の県境にある日本百名山の蔵王連峰は、古くからの山岳信仰の対象であり、平安時代中頃には空海の両部神道を唱える修験者が修行するようになった。