Iwakura (Shinto)

A yorishiro (依り代・依代・憑り代・憑代^?) in Shinto terminology is an object capable of attracting spirits called kami, thus giving them a physical space to occupy during religious ceremonies. Yorishiro are used during ceremonies to call the kami for worship. The word itself literally means approach substitute. Once a yorishiro actually houses a kami, it is called a shintai. Ropes called shimenawa decorated with paper streamers called shide often surround yorishiro to make their sacredness manifest. Persons can play the same role as a yorishiro, and in that case are called yorimashi (憑坐, lit. possessed person^?) or kamigakari (神懸り・神憑, lit. kami possession^?).

The concept and the use of yorishiro are not exclusive to Japan, but arise spontaneously in animistic cultures. In monotheistic religions animals and objects are just works of the world's creator, whereas to animists they are the natural residence of spirits, kami in the case of Japan.

Yorishiro and their history are intimately connected with the birth of Shinto shrines. Early Japanese did not have the notion of anthropomorphic deities, and felt the presence of spirits in nature and its phenomena. Mountains, forests, rain, wind, lightning and sometimes animals were thought to be charged with spiritual power, and the material manifestations of this power were worshiped as kami, entities closer in their essence to Polynesian mana than to a Western God. Village councils sought the advice of kami and developed the yorishiro, tools that attracted kami acting like a lightning rod.Yorishiro were conceived to attract the kami and then give them a physical space to occupy to make them accessible to human beings for ceremonies, which is still their purpose today. Village council sessions were held in a quiet spot in the mountains or in a forest near a great tree, rock or other natural object that served as a yorishiro. These sacred places and their yorishiro gradually evolved into the shrines of today. The very first buildings at shrines were certainly just huts built to house some yorishiro.

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Wikipedia