Naka joined Sega in 1984 and worked on games including Girl's Garden (1985) and Phantasy Star II (1989). He is the co-creator of the Sonic the Hedgehog series and was the president of Sonic Team at Sega until his departure in 2006. Yuji Naka ( 中 裕司, Naka Yūji, born September 17, 1965), credited in some games as YU2, is a Japanese video game programmer, designer and producer.