About 1806, in Edo City, a young Tengu (one of Japanese ghost) Torakichi (called 'Sendo') appeared, who claimed that he could come and go to the underworld; Atsutane was introduced to him and directly asked him about the other world and secrets of mysterious things, then Atsutane realized that the underworld really existed and exerted great or little influence on this world; and he thought that the boy's story surprisingly corresponded to the idea of the Dark and the Light which he had been considering for years; after that, with conviction of the idea and deeper worship, he continued his studies and practice of Kodo.
文化3年頃に江戸市中に冥府と往き来できると言う天狗少年仙童寅吉が出現し、奇しくも後に知人を介して邂逅する事により、本人から直接異境の有様や幽事の秘め事などを聞き質し、幽界冥府が厳然と実在し、大なり小なり深く現界に影響を及ぼしている有様に気づき、篤胤自らが常日頃考えていた幽顕の理念と奇しくも符節融合する事を悟り、幽顕一如を再確信すると共に敬神の念を更に深めて古道を敷衍し実践して行く事となる。