By mid afternoon I was almost to Iya and passed this grove of sacred trees. It is not marked on the map as a shrine, but it most certainly is a shrine. 100 years ago every single hamlet would have had a similar shrine, but around 100,000 of them were destroyed by the governments aggressive campaign to promote their new Amaterasu and Emperor centered "national" religion.
Some places resisted the government campaign which is why shrines such as this still exist. There was one small structure and several of the trees had an altar in front.
Thge biggest and most used altar was to Kojin, by far the most common kami in the Izumo region. With links to the kami of the hearth, the kami of the rice paddy, and the rough kami of the land, it is represented as a serpent made out of rice straw.
Most literature on "shinto" makes little mention of this kami, probably because it has no links to the national kami. I really need to spend some more time in Izumo asking people about Kojin. In my area the similar kami is called Omoto and is female.
I had known that nearby northern Hiroshima had a similar representation of the land kami, but I was really surprised last week as I was walking the back roads of southern Hiroshima to find a tree with a rope snake wrapped around it.....
All across Japan, from Kyushu to Tohoku, rope serpents are representative of the land kami. Why is it so unknown?