Onigajo (鬼ヶ城), literary means the castle of Ogre, is one of the UNESCO World Heritage sites located in Kumano, Mie Prefecture. It is also very famous national scenic beauty and registered as one of 100 best scenic beauties in Japan. It is a huge sea cave rocks raise by earthquake. The entire site is about 1km long.
That unique scenery is just like the castle of Ogre.
Tourist Info.
There are parking and restroom.
Access
0. at kumanoshi Station.
1. use local bus to Onigajohigashiguti.
45 min
New Wave Samurai Movie. 
映画好き集まれ！ 
Onigajo is the one of the national scenic beauties and natural monuments of Japan.
The legend said, in the time of Emperor Kanmu (early 9th century), the general Sakanoue no Tamuramaro marched this area to conquest the pirates here. The head of pirates was called Ogre. Sakanoue no Tamuramaro defeated the pirates and later, this rock was named under his legend.
This site is registered as The UNESCO World Heritage Site, "Sacred Sites and Pilgrimage Routes in the Kii Mountain Range."