Five bridges were built over the Kotsuki River in Kagoshima City. The bridges were constructed by Sangoro Iwanaga, a Higo mason, between Koka2(1845) and Kaei2(1849). This paper describes the construction method developed by Sangoro Iwanaga in Higo before he left for Satsuma. Sangoro Iwanaga constructed Mitsuyose Bridge with a segmental arch, and as a result, he established the techniques of fan masonry, double wheel stone, and multiple masonry. Sangoro Iwanaga learned from Bizen stonemasons the Bizen style of packing cobblestones inside the stone walls and the Makidomo stone wall technique.
