This structure comes from the philosophy of Esoteric Buddhism especially of Kukai (in his work "Sokushin jobutsu gi" (Attaining Enlightenment in This Very Existence)) and Kakuban (in his work "Gorin kuji myo himitsu shaku" (Secret Explication of the Mantras of the Five Wheels and the Nine Syllables)).
これらは密教の思想、特に空海（著作『即身成仏儀』等）や覚鑁（著作『五輪九字明秘密釈』等）の影響が強い。