The Sumitomo business was started in Kyoto, the historic capital city of Japan, nearly 400 years ago by Masatomo Sumitomo (1585-1652) and Riemon Soga (1572-1636).
Masatomo is regarded as the spiritual founder of the Sumitomo Group. Following an early career in the Buddhist priesthood, he established a shop in Kyoto that sold medicines and books. In accordance with the custom of his time, Masatomo produced written teachings for his household and disciples. One volume of these, which provided advice on the conduct of commercial activity, has come to be known as the "Founder's Precepts" and is the basis of code of conduct, still today, for the Sumitomo Group of companies.
Riemon, who was a disciple and brother-in-law of Masamoto, was the technological pioneer who set the Sumitomo business on the path to commercial success. Having studied copper refining, Riemon established the Izumia copper business in Kyoto in 1590. Until the late 16th century, Japanese copper merchants did not possess the technology to extract the silver contained in copper ore, which compelled them to export the ore with the silver intact. By learning and perfecting Western smelting methods, Riemon engineered a revolution in Japanese copper refining. The Sumitomo business was continued by Riemon's eldest son, Tomomochi (1607-1662), who entered the Sumitomo family through his marriage to Masatomo's daughter. Tomomochi moved the copper smelting business to Osaka, Japan's commercial capital at the time.
One of the epoch making events in the early days of the Sumitomo family was the 1690 opening of the Besshi Copper Mine on the island of Shikoku, across the Seto Inland Sea from Osaka. The Besshi Copper Mine was extremely productive and profitable, right up to the early 20th century. Consequently, it played a pivotal role in the birth of many core companies of the Sumitomo Group today. In 1891, Sumitomo formulated its Business Principles, which are based upon the "Founder's Precept" by Masatomo.
Article 1 explains the necessity of acting in good faith, in order to maintain the other party's trust.
Article 2 urges that social trends should be studied in order to meet social changes with active responses.
Article 3 advises against being attracted to easy profits or hastily drawn to the promise of profits before fully investigating the commercial viability of ventures.