A gate that stands in front of every Shinria shrine, allowing the spirits to travel to the mortal plane in times of need, and allowing the monks to pass on after death.
Often a Torii Gate will have engraved on it the many names of the spirits locally recognized, as well as the rules of passage for the gate. Most often these rules include cleanliness of ones body, and a small donation of some kind to serve as a gift for the local spirits.
A dedicated follower of the Shinrian faith will often recognize the dedication of the shrine and choose to pass through the gates as the local spirits would. Whether this be as simply as walkign through, or through other various means. One famouse Torii Gate such as the one the one at Myahm Agana requires one to fly through the gate as if they were a spirit riding the winds.