Sonic Team is a Japanese video game development division of Sega. The initial team was composed of developers from Sega's Consumer Development division, including programmer Yuji Naka, artist Naoto Ohshima, and level designer Hirokazu Yasuhara. The team took the name Sonic Team in 1991 with the release of Sonic the Hedgehog for the Sega Genesis. The game was a major success, and started the long-running Sonic the Hedgehog franchise. The next several titles were developed by Naka and Yasuhara in America at Sega Technical Institute, while Ohshima worked on Sonic CD in Japan. Naka returned to Japan in late 1994 to become the head of CS3, later renamed R&D #8. During this time, the division was branded with the Sonic Team name but also developed games that do not feature Sonic, such as Nights into Dreams (1996) and Burning Rangers (1998). Following the release of Sonic Adventure in 1998, some Sonic Team staff moved to the United States to form Sonic Team USA and develop Sonic Adventure 2 (2001). With Sega's diversification of its studios, R&D #8 became Sonic Team in 2000, with Naka as CEO and Sonic Team USA as its subsidiary. Sega's financial troubles led to several major structural changes in the early 2000s; the United Game Artists studio was absorbed by Sonic Team in 2003, and Sonic Team USA became Sega Studios USA in 2004. After Sammy Corporation purchased Sega in 2005, Sonic Team was restructured to become Sega's GE1 research and development department, and later, CS2.
In addition to the Sonic series, the company has developed other games for Sega, such as Nights into Dreams (1996) and Billy Hatcher and the Giant Egg (2003).. The 1991 release of Sonic the Hedgehog is considered one of the most important moments in video game history, as it propelled the Sega Genesis's sales and Sega displaced Nintendo as the leading video game company. Some of Sonic Team's games, such as the original Sonic titles and Nights, are considered by critics some of the best video games ever made.