Born in 1585, the second eldest son of a samurai family in Maruoka, Echizen Province, Masatomo Sumitomo moved to Kyoto at the age of 12.
It was a long-cherished dream of his parents for Masatomo to become a disciple of the priest Gyui Shonin Kugen, who was then leading a new sect of Buddhism called Nehan. Masatomo was named Kuzen, and practiced asceticism, acquiring the title of Monjuin. Later the Nehan Sect was deemed by the government to be one of the sects of Tendai. Displeased with this Masatomo left the priesthood, opening a shop for books and medicines under the name of Fujiya in Kyoto. This was during the Kan-ei era (1624-43), when Masatomo was 45 years of age.
Surviving works published by Masatomo include Ojoyoshu (“The Essentials of Salvation” by Genshin, a Buddhist monk) and Goseibai Shikimoku (“Formulary of Adjudications,” the legal code of the Kamakura shogunate). As an apothecary, Masatomo traded in such drugs as Hangontan, a well-known panacea. The signboard for Hangontan exists to this day.
Despite his departure from the priesthood, many people wanted to follow Masatomo. He wrote numerous letters, such as Monjuin Shiigaki and Ikai (instructions to descendants) to his followers and family members.
The teachings of Masatomo may be summarized as follows: always keep the principal virtues of “honesty, mercy and purity” in mind, respect the gods and Buddha, act with prudence and discretion, and always be frugal. These teachings, handed down through the generations, constitute the basis of Sumitomo’s corporate philosophy. Masatomo built a retreat called Sokenan near Seiryo-ji Temple in Saga, Kyoto, retiring there at the age of 63. He passed away in 1652 at the age of 68 and is interred at Eiyo-ji Temple in Kyoto.