Around 1983, Naka saw that Sega was looking for programming assistants. He decided to apply. After a short interview, he started working for Sega in April 1984. His first task was designing maps and checking floppy disks for a game called "Road Runner" for the SF-7000. Naka can't remember if the game was ever released. His first major project was a game called "Girl's Garden". He and Hiroshi Kawaguchi created it together as part of their training process.