Takatoshi moved to Tokyo when he was 14 years old, and later his older brother joined him. Ever since he was very young, he had shown outstanding business talent. But because of that, his jealous brother sent him back to Mie when he was 28 years old. He waited for 24 years until his older brother passed away before he could take over Echigoya. He opened a new branch in 1673; a large Gofukuya (Kimono shop) in Nihon-Bashi, a district in the heart of Tokyo. Later the Gofukuya devision separated from Mitsui, and is now called Mitsukoshi.
Traditionally, Gofukuya's provided products made to order; a visit was made to the customer's house (typically a person of high social class or who was successful in business), a order taken, then fulfilled. The system of accountancy was called "Margin transaction" . Mitsui changed this by producing products first, then selling them directly at his shop for cash. At the time, this was an unfamiliar mode of operation in Japan.
In 1683, Takatoshi opened an "exchange shop" in Tokyo. Soon the shop began providing goods to the government of the city of Edo. At the time, Edo's government had struck a business deal with Osaka. Osaka would sell crops and other material to pay its land tax. The money was then sent to Edo— but moving money was dangerous in middle feudal Japan. The "exchange shop" facilitated transfers without the risk.
In July 1, 1876, the first Japanese Private bank was founded, Mitsui bank (now called Mitsui Sumitomo bank). Its president was Takashi Masuda (b. 1848 - d. 1938)
