The shinbashira (心柱, also 真柱 or 刹/擦 ''satsu'') refers to a central pillar at the core of a
pagoda
A pagoda is an Asian tiered tower with multiple eaves common to Nepal, India, China, Japan, Korea, Myanmar, Vietnam, and other parts of Asia. Most pagodas were built to have a religious function, most often Buddhist but sometimes Taoist, ...
or similar structure. The shinbashira has long been thought to be the key to the Japanese pagoda's notable earthquake resistance, when newer
concrete
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...
buildings may collapse.
History
Hōryū-ji
is a Buddhist temple that was once one of the powerful Seven Great Temples, in Ikaruga, Nara Prefecture, Japan. Its full name is , or Learning Temple of the Flourishing Law, the complex serving as both a seminary and monastery.
The temple was ...
, the world's oldest wooden structure, was found to have in 2001 a shinbashira from a tree felled in 594 AD. Their examples continue in impending centuries in other ''tō'' (塔, pagoda) like the Hokkiji in
Nara
The National Archives and Records Administration (NARA) is an " independent federal agency of the United States government within the executive branch", charged with the preservation and documentation of government and historical records. It ...
Kyoto
Kyoto (; Japanese language, Japanese: , ''Kyōto'' ), officially , is the capital city of Kyoto Prefecture in Japan. Located in the Kansai region on the island of Honshu, Kyoto forms a part of the Keihanshin, Keihanshin metropolitan area along wi ...
.
Architecture
The pillar structure is made out of straight trunks of Japanese cypress (''hinoki''). The pillar runs the entire (but see below) length of the pagoda, and juts out of the top 'layer' of the pagoda, where it supports the finial of the pagoda. The
shinbashira is a typical element of Japanese pagodas facing regular earthquakes, but cannot be found in China or Korea, which are not or at least not frequently hit by earthquakes and where other methods were developed instead.
The initial architectural forms included the pillar ingrained deep within the foundation (''Shinso'' ja: 心礎) Hōryūji Gojū-no-tou 法隆寺五重塔, (Gojū-no-tō: 5-layered-pagoda) was found to be 3m below ground level.
At this time, pillars were tapered and became roughly circular from the point where they rose beyond the roof, starting as hexagonal from the base. This shaping was necessary as metal pieces were fit to the central pillar to support the spire. Later uses starting 12c involve them suspended just above the ground, thus making them suspensions like the Nikkō Tōshōgū Gojū-no-tū 日光東照宮五重塔 (1818) in Tochigi prefecture.
Size had a bearing on the fragmentation of the pillars found in the 8th century.
The central pillar of Gojuu-no-tou at Hōryūji has a height of 31.5 m with a diameter of 77.8 cm at base, 65.1 cm in the middle and approximately 24.1 cm at the midpoint on the spire. Such huge pillars had to be divided into three sections: from the base stone to the third floor; from the fourth story to the point where the spire begins, and the spire section. The shaft of a three-storied pagoda (''sanjuu-no-tou'' 三重塔), is divided between the second and third stories and again where the spire begins. During the 8c, shinbashira were erected on a base stone set at ground level. Example: Hokkiji Sanjuu-no-tou 法起寺三重塔 (742) in
Nara
The National Archives and Records Administration (NARA) is an " independent federal agency of the United States government within the executive branch", charged with the preservation and documentation of government and historical records. It ...
.
''(see Earthquake Resistance below)''
Earthquake resistance
Japan is an earthquake prone country, yet records show that only two of the pagodas have collapsed during the past 1,400 years owing to an earthquake. Hanshin earthquake in 1995 killed 6,400 people, toppled elevated highways, flattened office blocks and devastated the port area of Kobe. Yet it left the magnificent five-storey pagoda at the
Tō-ji
, also known as is a Shingon Buddhist temple in the Minami-ku ward of Kyoto, Japan.
Founded in 796, it was one of the only three Buddhist temples allowed in the city at the time it became the capital of Japan. As such it has a long history, h ...
Temple in nearby
Kyoto
Kyoto (; Japanese language, Japanese: , ''Kyōto'' ), officially , is the capital city of Kyoto Prefecture in Japan. Located in the Kansai region on the island of Honshu, Kyoto forms a part of the Keihanshin, Keihanshin metropolitan area along wi ...
unscathed, though it levelled a number of lower buildings in the neighbourhood. The reason traditionally attributed has been the shinbashira; newer research shows that the very wide eaves also contribute to the
inertia
Inertia is the idea that an object will continue its current motion until some force causes its speed or direction to change. The term is properly understood as shorthand for "the principle of inertia" as described by Newton in his first law ...
l stability of the pagoda. Overall deductions have not been very simplistic.
Some of structural engineer Shuzo Ishida's model pagodas have a simulated shinbashira attached to the ground, as was common in pagodas built during the sixth to eighth centuries. Others simulate later designs with the shinbashira resting on a beam on the second floor or suspended from the fifth. Compared with a model with no shinbashira at all, Ishida finds that the one with a central column anchored to the ground survives longest, and is at least twice as strong as any other shinbashira arrangement. Studies about shinbashira and their quake resistant attributes have been many. These studies are now materializing even in brick-and-mortar buildings like the
Tokyo Skytree
is a broadcasting and observation tower in Sumida, Tokyo. It became the tallest structure in Japan in 2010
''(see relevant links and citations for further reading on the other earthquake bearing of Japanese pagodas)''
Modern uses
As a result of studies into the shinbashira structure and its utility in earthquake-resistance it has, once again, come into use in new buildings and structures, including the
Tokyo Skytree
is a broadcasting and observation tower in Sumida, Tokyo. It became the tallest structure in Japan in 2010cancel out the swaying of the needle-like tower during an earthquake. According to an official with
Nikken Sekkei
Nikken Sekkei (日建設計) is an architectural, planning and engineering firm from Japan, with headquarters in Chiyoda, Tokyo. Today (2019), Nikken Sekkei ranks as the second largest architectural practice in the world.
Staff and Offices
As o ...
, which designed the structure, the concept was developed on the basis that pagodas rarely topple during earthquakes.
More recently in San Francisco the renovation of 680 Folsom Street, a fourteen-story 1960s steel building, inspired an ultra-modern iteration of the shinbashira: an 8-million-pound structural concrete core that can freely pivot atop a single sliding friction-pendulum bearing during a large earthquake. Tipping Mar, the engineering firm behind the design, used performance-based design and nonlinear time-history analysis to prove that the solution would meet the goals of the California Building Code.Se Putting a Good Spin on Value Engineering
See also
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Buddhist temples in Japan
Buddhist temples or Buddhist monasteries together with Shinto shrines, are considered to be amongst the most numerous, famous, and important religious buildings in Japan.The term "Shinto shrine" is used in opposition to "Buddhist temple" to mi ...
Japanese Buddhist architecture
Examples of Buddhist architecture in Japan
Japanese Buddhist architecture is the architecture of Buddhist temples in Japan, consisting of locally developed variants of architectural styles born in China.p=716/ref> After Buddhism arrived from ...
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List of earthquakes in Japan
This is a list of earthquakes in Japan with either a magnitude greater than or equal to 7.0 or which caused significant damage or casualties. As indicated below, magnitude is measured on the Richter magnitude scale (''ML'') or the moment magnitud ...
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Tō-ji
, also known as is a Shingon Buddhist temple in the Minami-ku ward of Kyoto, Japan.
Founded in 796, it was one of the only three Buddhist temples allowed in the city at the time it became the capital of Japan. As such it has a long history, h ...
* The Japanese page on the architecture of the 5-tier pagoda of Japan contains sections about the debated reason behind pagodas' quake-resistance – one of the two theories is the ''Shinbashira'', and also lists the types of styles in which the ''Shinbashira'' is employed in the building of the structure.
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Shinbashira (Tenrikyo)
In the Tenrikyo religion, the Shinbashira (真柱 "central pillar") refers to the "administrative and spiritual leader" of Tenrikyo Church Headquarters
Tenrikyo Church Headquarters (''Tenrikyo Kyokai Honbu'' 天理教教会本部) is the main ...