fourth genertaion
Sega and NEC simultaneously released the Genesis and TurboGrafx-16 just before Christmas. The two systems did very brisk business despite the fact that Nintendo had about a 90% share of the market for the Nintendo Entertainment System, proving that the market was ripe for new technologies. The more powerful Genesis quickly outpaced the TG-16's sales, and took a commanding lead starting in early 1990. In this year, Namco released Kyuukai Douchuuki, World Stadium '90, Final Lap 2, Pistol Daimyo no Bouken, Souko Ban Deluxe, Dragon Saber, Steel Gunner, Rolling Thunder 2, Golly! Ghost! and developed an unreleased prototype, Puzzle Club. In 1991, Sega released Sonic the Hedgehog, in response to the impending release of Nintendo's updated system, the Super NES.
Sega advertisements during the 1991 holiday season underscored the speed of the company's new mascot. Also in late 1991, Nintendo released the 16-bit Super NES to compete with the Genesis. Packaged with the new system was Super Mario World, a new game from the very popular Mario franchise. This was the true beginning of the 16-bit war.