The origin of the torii is genuinely uncertain; proposed derivations include indigenous Japanese development and diffusion from the Indian torana, the Chinese pailou or Korean gateways, and no single account commands agreement. Documentary references appear from around the tenth century, later than the shrines themselves, so the gate's early architectural history has to be reconstructed from indirect evidence. The familiar vermilion colour, associated with the sun and with protection from evil, is common but not universal: Ise Jingu itself keeps its torii in plain unpainted cypress, in keeping with the shinmei style's emphasis on unadorned wood as a sign of purity, and that whole shrine complex, gates included, is dismantled and rebuilt anew every twenty years in the rite called shikinen sengu, a practice recorded since the late seventh century that treats renewal itself, rather than the permanence of any single timber, as the mark of sanctity.
The most famous concentration, the thousands of closely spaced red torii climbing the hillside at Fushimi Inari Taisha in Kyoto, are votive: each is a commercial donation, its donor's name, business and the year cut into the post, offered in petition or thanks to Inari, kami of rice and of business prosperity, at a cost that today can run into the low millions of yen. The graphic torii now serves internationally as shorthand for Japan itself, though within the tradition it remains first a functional marker of sacred ground rather than a portable national badge.