Yamagaki-no-Ookashi is the great Oak tree designated as a natural monument in Akiruno City. Quercus Salicina, a large tree that has strong roots in huge rocks, is said to be over 300 years old and appears overwhelming. The appearance of standing on the exposed limestone with roots gives the impression of embracing the entire mountain, so it has come to be called the “Yamagaki-no-Ookashi”.  The small ridge on which the oak grows overlooks the mountains and villages in the Fukasawa area, making it look as if a giant tree is watching over the village.