The Torii gate is passage way from the physical to spiritual world. When passing through the gate it is also important to maintain the idea of cleanliness. An example would be a person who has experienced a death in the family with in the last year. By brining in negative energy or feelings it would defile the holy ground. Torii gates, and structures like them, are found in China, India, Vietnam, Laos, Thailand and all over Asia.  This particular torii gate is for the shitaya shrine, in the busy Shinagawa section of Tokyo.  It displays well the manner in which traditional architecture and culture is often juxtaposed, in this case literally, with contemporary society.