Located at mouth of the river overlooking the lake, the shrine provides a peaceful place from which to watch the lake. At the center of the shrine, an ordinary looking large smooth stone has been positioned, with circles carved in the stone floor around it in a series of concentric rings, resembling waves.  

That large stone, worn smooth by the action of the action of waves, provides a focal point at the very center of the circle. Or, perhaps, a place to sit.

A path leads northwest, back to the castle grounds.