The history of Sumitomo dates back to Masatomo Sumitomo (1585 – 1652), who opened a book and medicine shop in Kyoto in the 17th century. Masatomo left his teachings in the form of the “Founder’s Precepts,” in which he expounds concisely the points in conducting business. His precepts still serve as the foundation of the “Sumitomo spirit.”

In the beginning, the Founder’s Precepts call on us to “Not only in matters of business but in all situations, make efforts with deepest gratitude in every aspect” as well as to refine ourselves to develop a trustworthy character rather than just pursuing money-making endeavors. In the main text, the precepts emphasize the importance of honesty, prudence, and sound management.

Around the same time Masatomo’s brother-in-law Riemon Soga (1572 – 1636), who ran a copper smelting and coppersmithing business in Kyoto (under the trade name Izumiya), developed, with considerable effort, a copper smelting technology called “Nanban-buki(Western Refining)” to extract silver from crude copper. Tomomochi Sumitomo (1607 – 1662), the eldest son of Riemon, who became a family member of the House of Sumitomo by marrying a daughter of Masatomo, extended the business to Osaka, and disclosed the “Nanban-buki” technology to other copper smelters. Sumitomo/Izumiya thus came to be looked up to as the “head family of Nanban-buki,” and Osaka subsequently took the lead in the copper refining industry in Japan.

During the Edo Period, Japan was one of the world’s leading copper-producing countries. Starting from the copper trade, Izumiya went on to become a trader in thread, textiles, sugar and medicine, and prospered to the point where it was said that “No one in Osaka can compete with Izumiya.”

Izumiya then went into the copper mining business and opened the Besshi Copper Mines after obtaining permission from the Tokugawa Shogunate in 1691. The Besshi Copper Mines continued operations for 283 years, forming the backbone of Sumitomo’s business.”