Mitsutorii is a combination of three myojin-gate torii (a pillared gate-like entrance to a Shinto shrine), and it is sometimes called yotsuashi torii (four-legged torii) because it has four pillars.
三ツ鳥居（みつとりい）は、明神型鳥居3つを1つに組み合わせたもので、柱が4本になる為、四脚鳥居と呼ばれる事もある。