This shrine, located at the root of a giant cedar tree (Shato-no-Ohsugi), was commonly called “Sumiyoshi-sha” in the medieval and modern ages. A diary of Kasuga Taisha from the early modern age mentions that a priest took a ritual position “on the platform of Sumiyoshi” for the Kasuga Festival on March 13th, and the place is now a stone pavement in front of Iwamoto Jinja Shrine.
On the other hand, another document owned by Kasuga Taisha records a different name for the shrine, “Iwamoto-sha”. Supposedly, the name “Iwamoto-sha” was first given in 1868 (the first year of Meiji Period) to distinguish it from another auxiliary shrine also called “Sumiyoshi-sha” at Nizaka-cho, Takabatake, Nara. Just like other Sumiyoshi shrines, this shrine’s main gods are worshipped as rulers of the sea and poetry.