On the Development History of Arch Stone Bridges, and it's Engineer IWANAGA Sangoro, Chief of Stonemason, and ASO Tetsuya, Master Carpenter

Abstract

Late in the Edo era, the construction works have been promoted in parallel with the TENPOU reforms in the SATSUMA clan, and these successes have produced a factor of the modernization of Japan. ZUSHO Hirosato, principal of the clan, have actively promoted infrastructures, such as river improvement, drought countermeasure and transportation preparation. Both IWANAGA Sangorou, chief of stonemason, and ASO Tetsuya, master carpenter, have played important parts in these construction works.The construction techniques of arch stone bridge that came down from China early in the Edo era, have made rapid progress with the numbers of construction works and structure plans, under the step-up in the agricultural production and the economy of the clan late in the Edo era. Both the five stone bridges of multiple spans that crossed Kotsuki river and IWANAGA who produced the five bridges are monumental values in the development history of arch stone bridges.