Off the Pacific coast of Tohoku, the earthquake of March 11, 2011, a submarine earthquake was not merely huge, with Magnitude 9.0, but it brought tragedy to the whole North-Eastern coastal region of Japan.
Was the escalation of the disaster because the constructions were made of wood? No, even for constructions made of concrete; as it was liquid that flamed, the fire could spread under such phenomena.
Since 1870, when the Ministry of Construction was established, each time a big disaster occurred, building regulations in Japan have been revised. These changes required increased structural rigidity in newer buildings. The lessons in Wood Construction Arts, learned by the Master Carpenters from the earthquake disasters, have not been incorporated into the actual building regulations. The wisdom of the principles of "flexible post-and-beam construction" has been excluded from the regulations.
The Master Carpenters have constructed many historical buildings all over Japan since thousands years ago. And more than 90% of the constructions classified as national cultural heritages were constructed by them.
Japan is rich in seismic disasters since historical ages.
For master carpenters the earthquakes were always so awful that their power seemed to be infinite. It seemed impossible to construct a house that could survive after a strong earthquake without damages.
The master carpenters have designed the structures by giving an order to the structural members with which they might absorb some of the damage.
According to their way of thinking, even if a part of structure is broken, the total structure should avoid fatal collapse.
According to the way of thinking on which the actual building regulations are based, the structure cannot tolerate any damage.
The difference between these two ways of thinking is so big that the master carpenters’ way of thinking should have been eliminated. Now, its survival is threatened, though many existing historical buildings need its continued existence for their maintenance.
Is it correct to exterminate a historical way of thinking?
A statistical supposition has no meaning for a construction. We can always suppose that a greater earthquake can occur.
The historical way of thinking, which resembles the fail-safe or fault-tolerant system, seems more radical and practical.
Modern Engineering knows its problems and establishment of smart structure system is proposed. Isn’t it based on the fail-safe system?
We should preserve the Master Carpenters’ way of thinking and the Master Carpenters themselves and cultivate the Wood Construction Arts with them at least to maintain our historical cultural heritage and to reconstruct the stricken cities and villages.