Earthquake-Resistant Design as Proven by the Great Kanto Earthquake

The Daibiru-Honkan Building was a strong reflection of Watanabe’s ambitions in a variety of other aspects besides earthquake-resistant design. One was the deliberate use of materials produced in Japan. Although the main concern was profitability, Watanabe was a strong advocate of the domestic production of building materials for which he previously had to rely on foreign imports, so he encouraged Japanese manufacturers to produce those materials locally. A prime example is Japanese terra cotta, which Watanabe utilized after a trial production run was undertaken by Osaka Ceramics (now Nihon Network Support, Co., Ltd.). This was, in fact, the start of terra cotta production in Japan. In addition to domestically produced scratched tiles and linoleum (from TOLI Corporation) and plaster (from Sikama Chemical Industry Co., Ltd., now Asada Chemical Industry Co., Ltd.), he had Toyo Toki Company, Limited (now TOTO Ltd.) copy some urinals that he had brought in from New York. As a result of these efforts, roughly 90% of the materials used for the Daibiru-Honkan Building were produced in Japan.

Watanabe also had the intention of adopting the “actual costs plus additional remuneration” method of calculating construction costs based on the rationalist principles used in the U.S. In principle, the client would purchase the necessary materials and pay contractors only the cost of overhead labor. The contractor guarantees a certain construction schedule and pays specific compensation in the case of construction schedule delays. If actual costs exceed or fall short of the construction estimate determined at the start of the contract, the construction costs are adjusted by adding or subtracting a percentage of that amount to or from the original construction costs. This helped to keep construction costs in check and made the building more profitable after opening.