in 17th by Masatomo Sumitomo and Riemon Soga. Masatomo is regarded as the spiritual founder of the Sumitomo Group. They opened copper refining business and a copper workshop there. Based on long experiences of copper related products, the Sumitomo Copper Rolling Works was established to manufacture copper wires (bare wires), copper plates. and copper rods, which is the formation of the Sumitomo Electric Industries Ltd (SEI).