What is "sanmon"

A , also called , is the most important gate of a Japanese Zen Buddhist temple, and is part of the Zen shichidō garan, the group of buildings that forms the heart of a Zen Buddhist temple. It can be however often found in temples of other denominations too. Most sanmon are 2- or 3- bay nijūmon (a type of two-storied gate), but the name by itself does not imply any specific architecture.