japanese rain chain

Rain chain, a type of traditional Japanese drain pipe, continues to evolve while keeping in step with history of Japanese architectural development.

 

History and Evolution of Kusari-toi : Rain Chains

Kusari-toi, rain-chain, is a type of drain sprout that hangs vertically down from the lateral gutter on roofs, designed to guide collected rainwater to the ground. Vertical drain spouts are commonly made of pipes, not displaying the flow of water on its way to the ground, but in contrast, Kusari-toi is a functional ornament which provides visual pleasure for the observer as the rain water trickles down the chain from the roof down to the ground. It has been implemented in shrines and temples as well as residences in Japanese style architectures since long ago to eloquent the various emotions that Japan’s four seasons express. 
Kusari-toi is a form of Japanese architecture which was first implemented when constructing Sukiya-style buildings, or tea-houses for performing tea ceremonies. Sukiya’s architecture first appeared during the Azuchi Momoyama period (approx. 1558-1600 CE) when small tea-houses were called Sukiya in Japan. At the time, Tea masters preferred mundane and rustic aestheticism over formality and splendor, so natural elements were selected for Sukiya architecture. As a result, similar sensibilities can also be seen in Kusari-toi of that period as fibers from the outer layer of hemp-palm plants were woven into a rope called Shuro-nawa, and was hung from the eaves made of bamboo or wood so that rainwater could trickle down the rope to the ground, functioning as Kusari-toi, the original rain-chain.  
The shuro-nawa type of rain chain can still be found at the Edo-Tokyo Open Air Architectural Museum, next to the entrance of a house historically resided by each generation’s leader of Mitsui family, each successor inheriting the name Hachiroemon Mitsui.
As time passed, drain sprouts, which were formerly made of natural elements such as bamboo and wood, have evolved with the advancement of metal technology and metal materials such as copper were soon used. Rain chains also evolved from shuro-nawa ropes to linked metal chains and further developed to cup-shaped metal for improved water flow.  
The evolving rain chain, which is a functional drainage ornament designed specifically for traditional Japanese architecture, slowly saw its use expand to residential homes about a half century ago. The increasing inclination towards Western style homes during the following years reduced the number of rain chain being used. However, due to its captivating design, a revival is observed in recent years where architects increasingly incorporate it on buildings with Japanese tastes or transforming it as a façade on modern commercial buildings which are all new ideas that had not existed with the conventional perspective.

 

How to utilize Rain Chains

Rain Chains could be implemented on residential or commercial buildings as facades. On rainy days, water will flow naturally with weather changes, projecting a unique ambiance each time. Also, green plants may be incorporated to create green curtains.
Rain chains may be installed where drain pipes would be difficult due to the building’s structural design or on places where you would prefer not to display conventional looking pipes for aesthetic reasons. Or, on particularly long and narrow eaves that complicates installing gutters, rain chains could drain water straight down from the eaves which makes it a very simple method of managing rain water.
Also, rain chains could be an accent to a design. By incorporating traditional style on a modern building, Japanese atmosphere could be rendered. In particular, our products “Toh”, “Ta-ke” and “Tama” were developed by a designer and characterized by their clean, refined shapes, which could be seamlessly adopted onto buildings with highly stylized designs.

 

History and Application of Drain Pipes in Japan

Drain pipes are used in regions with a lot of rain to prevent rains digging the ground by dripping down from end of the eaves, or to prevent damage to the building from the rain.
Many dwellings during the Edo period in Japan were thatched houses, which dispersed the rain when falling to the ground, naturally preventing the rain drops to concentrate in one location so additional drains were not generally used. However, the architectural designs of temples, castles and shrines arrived in Japan during the Asuka period from China with many having ceramic roof tiles, so in order to prevent rain from dripping in a focused area, drain pipes made from bamboo and wood were applied to collect and guide rain water to the ground.
After the Edo period, as population concentrated in major cities, mainly Tokyo, the residences became increasingly clustered, which made rain water an issue among neighbors. Furthermore, drain pipes proliferated among residential buildings as well due to an official endorsement by the Tokugawa regime to install tiles on the roof instead of grass and wood, which was the predominant characteristic of Japanese traditional architecture, as the city’s fire preventative measure.
Because rain water passes through regularly, the drains deteriorated fast and required replacements every few years. For this reason, buildings with great importance; the temples, shrines and castles, were installed with gutters made of metals such as copper. Before the Edo period, metals were very scarce for general access, preventing residential usage.
After the Meiji period, copper sheets saw increased usage and sheet metal craftsmen popularized it by processing it as metal drain pipes. Copper has strong resistance to water but is softer than iron, making this material easier for processing, and in addition, when copper oxidizes it produces beautiful patina which gathered preference as roofing material over Japanese tiles in some homes.
In recent years, drain pipes made of various metal material are available due to the evolution of metal processing technology, including stainless steel, galvalume, etc.

SEO Inc. has been manufacturing rain chains since the 1960’s when cup shaped versions began its production. Ever since then, we have continued to develop new types of rain chains in various shapes and forms. Our products are presently being used on historical buildings such as Nikko Toshogu Shrine’s Museum and various highly stylized buildings designed by architects and design firms across the world. With the changes in our life-style, architectural design has been steadily shifting from traditional Japanese style to modern architecture, so in addition to traditional shaped rain chains, we aspire to create rain chains with new styles that reflect the change of times, with designs and patterns that could be incorporated into modern buildings. 

Lastly, Japan is blessed with four distinct seasons which brings multi-facetted natural phenomenon each time and as a culture we embrace it and find joy in them. It can be said that rain chains were born long time ago in response to the unique aesthetic sensibility that adores nature and, especially in this case, the act of enjoying the rain seasons in June and in the autumn season contributed to the birth of rain chains.

It is the goal of SEO Inc. to spread the use of rain chain, a unique building material born with the Japanese cultural back drop, to the rest of the world.

japanese rain chain
Shuro-nawa type rain chain Former residence of Hachiroemon Mitsui Edo-Tokyo Open Air Architectural Museum