A 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 possessed person or kami possession.
Yorishiro and their history are intimately connected with the birth of Shinto shrines. Early Japanese culture 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 essence to the Polynesian mana. 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 first buildings at shrines were likely just huts built to house some yorishiro. A trace of this origin can be found in the term 神庫, literally meaning "deity storehouse", which evolved into hokora (also written with the characters 神庫), one of the earliest words for a shrine. Most of the sacred objects found today in shrines (trees, mirrors, swords, magatama) were originally yorishiro, and only later became kami themselves by association.