A torii is a traditional Japanese gate most commonly found at the entrance of or within a Shinto shrine, where it symbolically marks the transition from the sacred to the profane (see Sacred-profane dichotomy). The presence of a torii at the entrance is usually the simplest way to identify Shinto shrines, and a small torii icon represents them on Japanese road maps.[note 1] They are however a common sight at Japanese Buddhist temples too, where they stand at the entrance of the temple's own shrine, called chinjusha and usually very small.

Their first appearance in Japan can be reliably pinpointed to at least the mid-Heian period because they are mentioned in a text written in 922. The oldest stone extant torii was built in the 12th century and belongs to a Hachiman Shrine in Yamagata prefecture. The oldest wooden torii is a ryôbu torii (see description below) at Kubô Hachiman Shrine in Yamanashi prefecture built in 1535.

Torii were traditionally made from wood or stone, but today they can be also made of reinforced concrete, copper, stainless steel or other materials. They are usually either unpainted or painted vermilion with a black upper lintel. Inari shrines typically have many torii.

The daiwa or Inari torii is a myōjin torii with two rings called daiwa at the top of the two pillars. The name "Inari torii" comes from the fact that vermilion daiwa torii tend to be common at Inari shrines, but even at the famous Fushimi Inari Shrine not all torii are in this style. This style first appeared during the late Heian period.