Known initially as Izumi-ya, Sumitomo began its operations in the fields of copper refining, trading, and mining. Its Shikoku Besshi Copper Mine first opened in 1691, and by 1888, mining operations had expanded enough to warrant the introduction of the "shop practices" concept as a way of manufacturing and repairing equipment and tools used at the mine. This marked the beginning of Sumitomo Heavy Industries, Ltd.