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  • John Barr

Zenecon: The Japanese Construction Phenomenon

By far the greatest force in the construction and, I would argue, the design of the Japanese built environment is the Zenecon. The word is a phonetic and abbreviated corruption of the English ‘General Contractor’ and refers to the large construction companies that dominate the industry in Japan. These are unlike construction companies in the UK. Here are some statistics on the biggest companies, commonly referred to as The Big Five:


Established : 1840

Paid Up Capital : £500,000,000

Employees : 7,527 (as of March 2016)


Established : 1892

Paid Up Capital : £300,000,000

Employees : 8,402 (as of March 2016)


Established : 1873

Paid Up Capital : £600,000,000

Employees : 8,007 (as of March 2015)


Established : 1804

Paid Up Capital : £400,000,000

Employees : 10,751 (as of April 2017)


Established : 1899

Paid Up Capital : £250,000,000

Employees : 7,307 (as of January 2017)

These companies are what we would call ‘management contractors’. They carry no plant or site workers on their books, hiring these in from sub-contractors on a contract-by-contract basis, but they all have extensive design and research departments. The employee numbers shown above, after making deductions for admin, marketing, sales staff etc, are all design, research or construction-management professionals. Takenaka, the smallest of the five, employs over two thousand registered architects, as does Obayashi. A breakdown of staff numbers is not readily available for the others but they will be similar. These five companies alone will employ over ten thousand registered architects. To put this in perspective, Nikken Sekkei, by a long way the largest architect practice in Japan, and fourth biggest in the world, employs a total of 2,547 staff of whom 1,044 are registered architects, half as many as any one of the Big Five Zenecon. And the architects employed by these companies are not just numerous, they are producing quality work. The design departments of any of the Big Five are well respected but perhaps in particular those of Takenaka and Kajima, which are recognised in their own right as being amongst the best design offices in Japan.

A huge portion of what we see, both buildings and infrastructure, when we walk around Japan has been designed and built by the Japanese Zenecon. But perhaps more important than what they do is the environment in which they do it. There are two striking differences between the construction industry in Japan and that in the UK: its collaborative nature and its investment in research. The emphasis on research is particularly striking. Whereas UK construction companies undertake almost no research it is vital to the Zenecon for a number of reasons. Firstly, the majority of construction contracts in Japan are negotiated and so Japanese contractors rely on research and the development of new and improved systems and techniques to differentiate themselves and attract customers. Secondly, the Japanese government expects large construction companies to undertake research to drive continuous improvement in the industry, and a significant and active research programme is a pre-requisite to accessing major public projects. And thirdly, Japan suffers from the same manual skills shortage as other developed countries and has addressed this issue through the development of sophisticated automation, not just in the factory but also on the building site.

This environment surrounds the whole industry but the Zenecon, especially the largest of them, sit at the centre of everything. They are unique in that they combine research, design and construction in a completely integrated model. Even the more widely known ‘name’ architects (Ito, Hasegawa, Kuma, SANAA, etc) can only achieve the larger or more challenging of their designs because they swim in the waters provided by the Zenecon who, apart from providing the expertise to build them, often undertake the detail design and production packages for these projects. Many architects benefit from this situation; I have benefitted from it myself. Small practices are able to design relatively large projects because they can harness the manpower and expertise of the Japanese general contractor not only for research and construction but also, when necessary, for assistance with the production package. This is possible because of the second way in which the Japanese industry differs from the industry in the UK – its collaborative nature.

Whilst the Zenecon do occasionally design and build individual houses, most are designed and constructed by specialist house-building companies. Two of the largest are Sekisui House and Daiwa House, both of which employ more than 15,000 staff and have, between them, built in excess of 3 million homes. In the current economic climate these large companies have started to eclipse all but the largest of the general contractors in terms of turnover and they have adopted the Zenecon model, with an emphasis on continuous research, improvement and automation. In comparison to the Zenecon the Housebuilders are relative newcomers, most having been established in the mid twentieth century, and they market their homes very much as consumer items. It is perhaps no coincidence that Toyota (the car manufacturer) entered this market some time ago; Toyota Homes is relatively small but still produces more than 5,000 homes a year.

And so the Housebuilders play a significant role in the creation of the built environment in Japan, and consultant architects and engineers play their part too, but the Zenecon are the very heart of the Japanese built environment.

Since the Meiji restoration in 1868, which effectively marks the birth of modern Japan, the Zenecon have driven forward the creation of the built environment, certainly the urban environment, and yet we know little of them in the West. It seems that, whilst we recognise the contribution of industrial giants from other fields to the creation of modern Japan: Sony; Nikon; Honda, we have a blind spot when it comes to architecture, preferring to concentrate our interest and attention on a handful of individual architects. Whilst not denying that the work of these individual architects can be interesting and worthy of study I would suggest that it tells us little about what has driven and shaped Japan's built environment over the last century or more. To discover that, we should pay more attention to the phenomenon of the Zenecon.

Facade detail from Takenaka Head Office building in Osaka showing the restrained use of materials and the refined detailing and proportion that features in much of their work.

Designed and built by Takenaka, 1965.

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