This paper aims to analyze the business activities of Mitsui Bussan Kaisha (hereafter MBK) in its founding period, 1876-1893. Commonly accepted views are as follows : (1) Until the first half of 1880s MBK mainly dealt as a purveyor for the Japanese government, acquiring business know-how in the process. (2) In the 1890s it shifted its business activities from government-related ones, dealing in rice and blankets, to non-government related ones, dealing in coal, cotton and machines. (3) MBK kept turning a profit except in 1881. (4) In this way MBK grew from a purveyor to a modern trading company. However, these facts do not mean that MBK's business activities progressed satisfactorily in the period under consideration. In the mid-1880s it accumulated bad assets, mainly in London and Shanghai. It had to write them off by retaining the profit relating to its own ships and trading, and delaying the depreciation of its ships. In the beginning of the 1890s, it accumulated bad assets once again in the form of mines and fisheries in Hokkaido. It had to write them off by transferring the capital which it had been setting aside from profits since its establishment. In this process, the foreign branches in London and Shanghai, which MBK had established at great expense in the 1880s, made a large contribution to the company by trading in many kinds of goods. The London branch in particular, located at the center of world trade, was to become essential to MBK' s development from the second half of the 1890s.
