Izumo Taisha (Izumo Grand Shrine) is one of the most ancient and important Shinto shrines in Japan. No record gives the date of establishment. Located in Izumo, Shimane Prefecture, it is home to two major festivals. It is dedicated to the god Okuninushi (Okuninushi-no-mikoto), famous as the Shinto deity of marriage.
A style of architecture, taisha-zukuri, takes its name from the main hall of Izumo-taisha. That hall, and the attached buildings, were designated National Treasures of Japan in 1952. According to tradition, the hall was previously much taller than presently. The discovery in the year 2000 of the remains of enormous pillars has lent credence to this.
Several other buildings in the shrine compound are on the list of Important Cultural Properties of Japan.
According to the two oldest chronicles of Japan, the Kojiki and Nihon Shoki, when Ninigi-no-Mikoto, grandson of the Sun Goddess Amaterasu, descended from the heavens, the god Okuninushi granted his country to Ninigi-no-Mikoto. Amaterasu was much pleased by this action and she presented Izumo-taisha to Okuninushi. At one time, the Japanese islands were controlled from Izumo, according to Shinto myths. Izumo, known as the realm of gods or the land of myths, is Izumo-taisha's province. Its main structure was originally constructed to glorify the great achievement of Okuninushi, considered the creator of Japan. Okuninushi was devoted to the building of the nation, in which he shared many joys and sorrows with the ancestors of the land. In addition to being the savior, Okuninushi is considered the guardian god and god of happiness, as well as the god who establishes good relationships.
According to the Nihon Shoki, the sun goddess Amaterasu said, "From now on, my descendants shall administer the affairs of state. You shall cast a spell of establishing good relationship over people to lead them a happy life. I will build your residence with colossal columns and thick and broad planks in the same architectural style as mine and name it Amenohisu-no-miya." The other gods were gathered and ordered by Amaterasu to build the grand palace at the foot of Mt. Uga. There is no knowledge of exactly when Izumo-taisha was built, but a record compiled around 950 (Heian-era) describes the shrine as the highest building, reaching approximately 48 meters, which exceeds in height the 45 meter-tall temple that enshrined the Great Image of Buddha, Tōdai-ji. This was due to early Shinto cosmology, when the people believed the gods (kami) were above the human world and belonged to the most extraordinary and majestic parts of nature. Therefore, Izumo-taisha could have been an attempt to create a place for the kami that would be above humans.
According to Kojiki, the legendary stories of old Japan, and Nihon Shoki, the chronicles of old Japan, Izumo-taisha was considered the largest wooden structure in Japan when it was originally constructed. Before being known as Izumo Oyashiro or Izumo-taisha, the shrine was known as Okami-no-miya in Izumo, Itsukashinokami-no-miya, Kizuki-no-Oyashiro, Kizuki-no-miya, or Iwakumanoso-no-miya.
Evidence of the original Grand Shrine has been found. For example, part of one of the pillars for the structure was found: three cedar trees with a three-meter diameter at its base. It is on display at the shrine. Although there is not much early evidence one can see when visiting, there is a shop just before the main entrance that has a smaller scale model of the original main structure made by local college students.