October used to be called Kanazuki in the Japanese lunar calendar.
In the olden days, gods all over Japan got together in the country of Izumo (today Shimane prefecture) in order to hold a meeting in October. All the deities left their countries for Izumo, leaving no gods behind in their countries. The godless month called Kanazuki ( KA NA ZUKI means GODS, NOT, and MONTH respectively.) is a widely accepted theory.
Accordingly, the country of Izumo, was called Kamiarizuki to the contrary, or a month of gods (a month when gods are available). For seven days between October 11 through 17 in the lunar calendar, gods came together at Izumo –Oyashiro (Izumo Shrine) from around the country.
There was a belief that divine acts, or facts of life unpredictable by humans were decided by the gods at the conference where humans destinies were discussed, particularly including decisions to be made about who get married to whom. It was at these meetings that couples who had had no mutual relations whatsoever, were tied each other with a red thread so as to get married. Accordingly, people have a religious faith in Izumo Shrine as god of marriage as well.
God enshrined at Izumo Shrine is Okuninushinoookami, or the integrated Great God, which is also called god yearned over by people as Daikoku-sama. This God developed the country of Japan. In Nihonshoki, or the oldest book of Japanese history says that when the God completed constructing the country, ceded to Amaterasu-oonokami, Godess of the Sun, control of Japan concerning material things, which is called Concession of the Country. And God is supposed to control spiritual things, with the conference left for ordaining destinies of ordinary people in the course of discussion.
At this time, Izumo Shrine holds the event of Kamiari-festival, festival of gods.
The highest level of the Shrine is the place of conference for gods.
Gods nationwide stay at the long shrines, called Eastern 19 shrines as well as Western 19 ones located on the premise of the Shrine. During the festival of gods, shimenawa, or the divine ropes are stretched and the offerings are given to the shrine.
In the region of Izumo, after the festival of gods is over, gods return to their counties.
On October 17 and 26, the Shrine holds the festival of Karasadesai, one for gods incoming and outgoing. On 17, gods leave the Shrine and leave the country of Izumo on 26.