Ikaruga Oji Shrine was the oldest shrine of all the Kumano Kujyu-ku (99) Oji shrines, which were famous training places for Kumano Shugendo (mountain practice). Together with other Oji shrines such as Shioya, Kirime, and Iwashiro shrines, this shrine flourished in the Heian period. The fact that Fujiwara no Munetada wrote in his diary “Chuyuki” in 1109, “We passed through Inami Village and went and worshipped at Ikaruga Shrine” shows that the shrine had already existed in the late Heian period (794-1132). This historic shrine has completely disappeared without leaving any trace. Only a stone monument stands where it used to be located. The area around the ruin is called Hikarigawa, which is said to be a phonic transformation of Ikaruga. The ruin of Ikaruga Shrine is designated as a cultural property by Inami Town.