Tea house has an entrance 60cm in height and width called Nijiri-guchi or Nijiri entrance. Nijiru means “to move forward on your knees with both hands down on the floor”.
Nijigi-guchi is said to be introduced by  Sen no Rikyuu who had this idea when he saw fishermen ducking to enter their boathouse in Hirakata City, Oosaka, and applied it to his Nijyou tea house. It is customary that upon entering a tea house, visitors bow their heads, kneel down with their hands on the floor and move forward with their knees. Nijigi-guchi is regarded as a boundary to separate the inside of a tea house from the outside world. The low entrance makes any visitor regardless of their social status humbly bow upon entering and it allows the cleansing of impurities from the outside world before entering the tea room.
Nijiri-guchi also has a spatial stage effect. Tea house is usually small. But by entering through an even smaller nijigi-guchi, visitors feel that the tea house is higher and deeper than it actually is.    
Nigiri-guchi is an original concept that embodies a spirit of humbleness which is a virtue unique to Japan.