game. During the late 1980s and early 1990s, a rivalry formed between Sega and Nintendo due to the release of their 16-bit video game consoles: the Sega Genesis and the Super Nintendo Entertainment System. Sega needed a mascot character that would be as synonymous with their brand as Mario was with Nintendo. Sega wanted a killer app and character that could appeal to an older demographic than preteens, demonstrate the capabilities of the Genesis, and ensure commercial success in North America. Sega held an internal competition to submit characters designs for a mascot. Ohshima designed a blue hedgehog named Sonic, who was inserted into a prototype game created by Naka. The Sonic design was refined to be less aggressive and appeal to a wider audience before the division began development on their platform game Sonic the Hedgehog. According to Ohshima, Sega was looking for a game that would sell well in the United States as well as in Japan. Ohshima and Naka already had the game and character ready, with Ohshima having worked with Sega's toy and stationery department on design ideas. Ohshima claims that the progress they had already made encouraged the company to select their proposal, as theirs was the only team to have put in a high amount of time and effort. This left him confident their proposal would be selected. The Sonic the Hedgehog project began with just Naka and Ohshima, but grew to involve two programmers, two sound engineers, and three designers. Hirokazu Yasuhara joined to supervise Naka and Ohshima and develop levels, and became the lead designer. He satisfied Naka's request for a simple, one-button design by having Sonic do damage by jumping. Sonic the Hedgehog was released in 1991 and proved a major success, contributing to millions of sales of the Genesis. The development team took the name Sonic Team for the game's release. Naka has referred to Sonic Team as only a "team name" at this point. 1994–1998: Re-establishment and new intellectual properties Shortly after the release of Sonic the Hedgehog, Naka, Yasuhara, and a number of other Japanese developers relocated to California to join Sega Technical Institute (STI), a development division established by Mark Cerny intended as an elite studio combining the design philosophies of American and Japanese developers. While Naka and Yasuhara developed Sonic the Hedgehog 2 with STI, Ohshima worked on Sonic CD, a sequel for the Sega CD