Mount Kōya (高野山, Kōya-san) is the common name of a huge temple settlement in Wakayama Prefecture to the south of Osaka. In the strict sense, Kōya-san is the so-called "mountain name" sangō (山号) of the Kongōbu-Temple (金剛峯寺, Kongōbu-ji), the ecclesiastical headquarters of the "Koyasan Shingon School".First settled in 819 by the monk Kūkai, Mount Kōya is primarily known as the world headquarters of the Kōyasan Shingon sect of Japanese Buddhism. Located on an 800 m high plain amid eight peaks of the mountain (which was the reason this location was selected, in that the terrain is supposed to resemble a lotus plant), the original monastery has grown into the town of Kōya, featuring a university dedicated to religious studies and 120 sub-temples, many of which offer lodging to pilgrims. Mount Kōya is also a common starting point to the Shikoku Pilgrimage (四国遍路, Shikoku Henro) associated with Kūkai.
The mountain is home to the following famous sites:
Kongōbu-ji (金剛峯寺), the head temple of the Kōyasan Shingon Buddhism. Located roughly in the middle of the sanctuary, Kongobuji is colloquially known as "Kōyasan-Issan", literally meaning "the mountain of Kōya". The temple was built by the warlord Hideyoshi Toyotomi for the mass of his mother when she died. Originally named Seiganji, it was later renamed Kongobuji in the Meiji Era.
Danjogaran (壇上伽藍), at the heartland of the Mount Kōya settlement. Garan is a name for an area that has the main sacred buildings: a main hall, several pagodas, a scripture storage, a bell tower, a lecture hall, and other halls dedicated to important deities. There is also a shrine dedicated to the Shintō-gods of that mountain area and in front of it an assembly hall (Sannō-dō). Danjō Garan is one of the two sacred spots around the Mount Kōya.
Konpon Daitō (根本大塔), the "Basic Great Pagoda" that according to Shingon Buddhism doctrine represents the central point of a mandala covering all of Japan. Standing at 48.5 m tall and situated right in the middle of Koyasan, this pagoda was built as a seminary for the esoteric practices of Shingon Buddhism. This pagoda and the Okunoin Temple form a large sanctuary.
Sannō-dō (山王堂), an assembly hall for special ceremonies dedicated to the Shintō-gods guarding the area
Okunoin (奥の院), the mausoleum of Kūkai, surrounded by an immense graveyard (the largest in Japan)
Kōyasan chōishi-michi (高野山町石道), the traditional route up the mountain with stone markers (ishi) every 109 metres (chō)
Daimon (大門), the main gate for Mount Kōya. This mammoth gate stands as the main entrance to Kōyasan. It is flanked on each side by Kongo warriors who guard the mountain.
Tokugawa Family Tomb. This mausoleum was built by the third shōgun Iemitsu Tokugawa. It took ten years to build and is architecturally representative of the Edo Period. First Edo shōgun Ieyasu is enshrined on the right and the second shōgun Hidetada on the left. The Structure is decorated with carvings and brass fittings.
It also houses a replica of the Nestorian stele.In 2004, UNESCO designated Mount Kōya, along with two other locations on the Kii Peninsula, Yoshino and Omine; and Kumano Sanzan, as World Heritage Sites "Sacred Sites and Pilgrimage Routes in the Kii Mountain Range".The complex includes a memorial hall and cemetery honoring Japanese who were imprisoned or executed for committing atrocities during World War II.