Iwafune Jinjya (the Iwafune Shrine) worships Nigihayashi no Mikoto who was a grandchild of Amaterasu Omikami. It is said that Nigihayashi no Mikoto came to this place from the air by Ame no Iwafune. The size was 12 meter (height) x 12 meter (width). Then Ame no Iwafune became a huge rock. The Iwafune Shrine was built in front of the huge rock.
The shrine has a rocky cave. Since the medieval era, many practitioners of Shinto and Shugendo visited the rocky cave for training their bodies and souls. You can challenge it even now.
Pleae note that the inside of the rocky cave is very dark and slippy. If wearing summer wears such as a t-shirt and short pants, you may not be allowed to entre into the cave. Please ask staff of the shrine whether to get in the cave before challenging.
Iwafune Jinjya
19-1 Kisaichi 9 Chome Katano City
Tel: 072-891-2125
http://www.osk.3web.ne.jp/~iw082125/index-j.html