The word Garan is derived from the Sanskrit word samgharama, meaning a quiet and secluded place for Buddhist monks to gather and practice.

In 816, the founder of Shingon Buddhism in Japan, Priest Kukai (774 to 835) began the planning and construction of this BUddhist monastic complex deep in the mountains of Koyasan as a place for meditation far from worldly distractions.

Kondo
Kondo Hall is the main hall of Koyasan Kongobuji temple located in Dai Garan. The many rituals and ceremonies are held here. The Kondo enshriens a statue of the Medicine Buddha that is not displayed, flanked by two large hanging mandalas, each with its own separate altar. Wall paintings show the eight offering bodhisttvas in the corners, and a beautiful large mural of the Buddha's enlightenment on the north side of the Kondo.

Daito
Konpon Daitoh is a great tower and one of the main symbols of Koyasan. It was a fundamental part of Priest Kukai's layout of the Garan. Originally, it was constructed in the time of priest Kukai and priest Shinen in 9th century. It enshrines a three-dimensional mandala, with the statues of Dainichi Nyorai of Matrix Realm, and the Four Buddhas of Diamond Realm. This tower is the temple for the Buddhist statues of Mandala of the Two Realms. There are 16 columns and each of them has the paining of 16 Bosatsu. This daitoh is the first Taho style tower constructed in Japan.

Miyashiro
Enshrines Niu Myojin and Koya Myojin, local protectors and god of Koyasan. When Priest Kukai consecrated Koyasan in 819, he invited two Shinto Gods to remain here to protect the area. Current shrines were constructed in 1594, and registered as national important cultural assets.

Miedo
It was originally the place wher Priest Kukai used for meditation.

Fudo-do
This hall dedicated to Fudo is the oldest building in Koyasan. It was constructed in 1198. It is registered as the national treasure of Japan. The bilding is uniquely constructed combining features of Heian architecture of both residentials and temples.

Western Tower
It is the twin tower of Daito. To represent the world of Esoteric Buddhism of Vairocana, this tower represent the Diamond Realm. The current tower was reconstructed in 1834. They are thirty-six pillars inside, and with central pillar these represent the thirty-seven deities of the Kongokai Mandala. Five BUddhas are enshrined here, with the central Buddha being Mahavairocana of the Kongokai surrounded by the four Buddhas of the Taizokai. This demonstrates the teaching of the non-dulity of the two mandalas. It is registered as the national historic site.

Daiedo
Enshrines Amidanyorai. This building was constructed in 1848.