SIMS was founded as a collaboration between Sega and Sanritsu, who had previously acted as a subcontractor for Sega mainly in the arcade market. The last game to be developed under the Sanritsu label was Fantasy Zone Gear for Sega's Game Gear. Upon the foundation of SIMS, 50 of Sanritsu's staff were transferred to the new company, which programmed and ported games for most of Sega's platforms in the nineties. At the same time, Sega took over the entire ownership of the company. However, on June 25, 2004 the president of SIMS, Noboru Machida, took back all the stocks and the company regained its independence.