鎖樋, kusari doi
Rain chains (Japanese: 鎖樋, kusari doi, literally “chain-gutter”) are alternatives to a downspout. They are widely used in Japan. Their purpose is largely decorative, to make a water feature out of the transport of rainwater from the guttering downwards to a drain or to a storage container. (Rainwater is sometimes collected for household usage.) They can be found on temples.
Rain chains are typically either a series of metal cups, chained together with a hole in the bottom of each, or chain links that span vertically. Rain water run-off gets distributed from a rooftop gutter downward through the rain chain. (“Rain chain,” 2011)
Rain chain. (2011). Wikipedia, the free encyclopedia. Retrieved March 4, 2011, from http://en.wikipedia.org/wiki/Rain_chain