The Pagodas of Japan

Honestly Lay Bare read a fascinating article this week about Japanese pagodas.

As The Economist tells it scholars over the ages have been mystified as to how these tall, wooden buildings cope so well with the earthquakes and typhoons that plague Japan. Many have been struck by lightning and burned to the ground. Others have been torched by marauding warlords. Fire was a perennial hazard in Japan when wood and paper buildings were the norm.

But, remarkably, only two of the country’s hundreds of wooden pagodas have collapsed over the past 1,400 years as a result of violent shaking.

The disastrous Hanshin earthquake of 1995 killed more than 6,400 people, toppled elevated highways, flattened office blocks and devastated the port city of Kobe. Yet the magnitude 6.9 shock left the magnificent five-storey pagoda at the Toji temple (pictured above) in nearby Kyoto unscathed, even though it levelled a number of lower structures in the neighbourhood.

You can see the Toji pagoda soaring 55 metres (180 feet) into the sky from the train as it pulls into Kyoto station. Though burned down four times since it was first erected in 826 by the master builder Kobodaishi, the current building has stood its ground since 1644. It was the tallest structure in Japan until the 36-storey Kasumigaseki Building was erected in 1968. The slightly smaller Horyuji pagoda in Nara was built in 607 and is thought to be the oldest multi-storey wooden structure in the world.

So, why don’t they topple over at the first tremor?

For two reasons. First, as the structure begins to sway, the heavy-tiled roof covering the extended eaves of each storey acts like the long pole with weights on the ends that a tightrope walker uses to steady himself. In both, the large “radius of gyration” means the shaking has a lot of inbuilt inertia to overcome.

Second, as the loosely stacked storeys slide to and fro—with each consecutive floor moving in the opposite direction to the one above and below—they collide internally with the trunk-like shinbashira dangling through the central well of the building. With each collision, they dump more of their kinetic energy into the massive column—trying vainly to make it swing like a pendulum.

Like all great buildings, a Japanese pagoda is as much a machine as a structure.

Engineers distinguish carefully between the two. Great pains are usually taken to ensure that structures, although flexible, are incapable of swivelling or sliding at their joints as machines do.

Otherwise, they may collapse in a heap.

What the pagoda builders realised was that they could use controlled motion at the joints of a building to help it dissipate sudden stresses imposed on its various members.

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Honestly Lay Bare could not escape the - perhaps far fetched but none the less valid - links to the internal control structures that we build and assess each day.

What really intrigued us was whether these modern day disciplines have learnt the lessons of the last 700 years.

How do our internal control and risk management framework use controlled motion to dissipate sudden stresses?

Are our frameworks flexible living beasts like a pagoda or are they destined to be the first to fall in a financial earthquake like that of the global financial crisis?

How many risk management structures were found to be inadequate about September / October 2008?

One would suggest that modern day risk management and internal control structures could learn a lot from 14th century Japanese pagoda builders!