Oi Shrine is a small village shrine on the shore of the Nakaumi. It is listed in the Izumo Fudoki and therefore must be at least 1300 years old. In the Fudoka it was called Oisha and the kami enshrined was Okuninushi. However the main kami is now Amaterasu, along with Amenokoyane, Nakatsutsu (one of the Sumiyoshi kami), Yamato Takeru, & Homuda Wake (Ojin), along with Okuninushi.
It woud be interesting to know why this whole slew of Yamato kami came to supplant the local Okuninushi, but I can find no information as to when or why this happened.
There is a small Inari shrine next to the main shrine, and, like all the shrines in the region, altars to the local Kojin, in this case 4 in total. Before the twentieth Century these would have been out in the local communities, but the government, in their bid to strengthen their new Shinto religion, closed many of the local shrines and forced the local people to move their altars/shrines to a central shrine more often than not enshrining a "national" kami.
It is obvious that these Kojin altars are the site of much more activity than the main shrine.