In Shinto, shintai, or go-shintai when the honorific prefix go- is used, are physical objects worshipped at or near Shinto shrines as repositories in which spirits or kami reside. Shintai used in Shrine Shinto (Jinja Shinto) can be also called mitamashiro.
In spite of what their name may suggest, shintai are not themselves part of kami, but rather just temporary repositories which make them accessible to human beings for worship. Shintai are also of necessity yorishiro, that is objects by their very nature capable of attracting kami.
The most common shintai are man-made objects like mirrors, swords, jewels (for example comma-shaped stones called magatama), gohei (wands used during religious rites), and sculptures of kami called 神像, but they can be also natural objects such as rocks (shinishi), mountains (shintai-zan), trees (shinboku), and waterfalls (shintaki) Before the forcible separation of kami and Buddhas of 1868 (shinbutsu bunri) a shintai could even be the statue of a Buddhist deity.
Famous shintai include the mirror (part of the Imperial Regalia of Japan), Mount Miwa, Mount Nantai, the Nachi Falls, and the Meoto Iwa rocks. Many mountains like Mount Miwa or the Three Mountains of Kumano (Kumano sanzan) are considered shintai and are therefore called shintaizan. The most widely known and renowned shintai is Mount Fuji.
A yokozuna, a wrestler at the top of sumo's power pyramid, is a living shintai. For this reason, his waist is circled by a shimenawa, a sacred rope which protects sacred objects from evil spirits. A kannushi, that is, a Shinto priest, can become a living shintai when a kami enters his body during religious ceremonies.
The founding of a new shrine requires the presence of either a pre-existing, naturally occurring shintai (for example a rock or waterfall housing a local kami), or of an artificial one, which must therefore be procured or made to the purpose. An example of the first case are the Nachi Falls, worshiped at Hiryū Shrine near Kumano Nachi Taisha and believed to be inhabited by a kami called Hiryū Gongen.