Sega Enterprises president Hayao Nakayama decided Sega needed a flagship series and mascot to compete with Nintendo's "Mario" franchise. Nintendo had recently released "Super Mario Bros. 3", at the time the bestselling video game ever. Sega's strategy had been based on porting its successful arcade games to the Genesis; however, Nakayama recognized that Sega needed a star character in a game that could demonstrate the power of the Genesis's hardware. An internal contest was held to determine a flagship game, with a specific focus on the American audience. Among the various teams working on proposals were artist Naoto Ohshima and programmer Yuji Naka. The gameplay of "Sonic the Hedgehog" (1991) originated with a tech demo created by Naka, who had developed an algorithm that allowed a sprite to move smoothly on a curve by determining its position with a dot matrix. Naka's prototype was a platform game that involved a fast-moving character rolling in a ball through a long winding tube. Sega management accepted the duo's project and they were joined by designer Hirokazu Yasuhara.