Shinto Shrines are climbing challenges marked by torii gates, each ending at a summit shrine that rewards a major charm. Ghost of Tsushima has 17 of them: 16 on Tsushima and one on Iki Island.
Find the torii gates at the foot of the climb and follow the path over broken bridges, cliffs and ledges to the top. Honor the shrine with R2 to collect its charm.
Most shrines let you teleport back to the start. Once you have honored it, find the closest torii gate and use R2 on the white circle.
In Izuhara only Stone Dragon and Winding Mountain need the Grapple Hook. Leave the rest of the hook shrines until after you get it in the story.