This is an entrance to a Shinto Shrine where the shimenawa is affixed to it's traditional place. The sacred origins of the shimenawa are told in the following tale... The Sun Goddess Amaterasu was so appalled at the wickedness of the world that she took refuge in a cave. Her absence deprived light to all so the God Futotama coaxed her to come out. Upon doing so, Futotama then barred Amaterasu's reentry to the cave with a "taboo rope which prevents any return."