The Sumitomo Clan traces its roots to a bookshop in Kyoto founded circa 1615 by a former Buddhist priest, Masatomo Sumitomo.[1] Considered its spiritual founder, even today management of the group is guided by his "Founder's Precepts", written in the 17th century.[1]
It was copper that made the company famous. Riemon Soga, Masatomo Sumitomo's brother-in-law, learned Western methods of copper refining. In 1590 he established a smelting business named Izumiya, literally meaning "spring shop".[1] The advanced techniques, which Riemon perfected, allowed the extraction of silver from copper ore, something which Japanese technology had as yet been unable to accomplish.[1]
The smelting and smithing business, which was begun in Kyoto, was moved to Osaka by the late 17th century.[1] and Soga passed control of the company to his son Tomomochi who managed its transformation into a major trading house[2] during the Edo period[3] Sumitomo began to export copper,[4] import silk,[4] and provide financial services.[5] By 1691 copper mining had been added to the portfolio.[6][7][8]
The Meiji Restoration allowed Sumitomo to import and utilize Western machines and techniques in its mines.[6] Sumitomo soon branched out into even more business areas entering the machine and coal industries, as well as the forestry, banking and warehousing businesses[6] becoming a zaibatsu,[3] or business conglomerate.
In 1940s after World War II, almost all clans including the Sumitomo Clan were dissolved by GHQ & Japanese government.
As a result, although there are many companies still using a common word "Sumitomo" in their corporate names, the companies are managed independently listed on Tokyo and other stock exchanges with highly dispersed shareholders. Therefore, there are no relationships among the companies using Sumitomo's name (the companies are not in one group).