Developed by Ken Thompson (software, also Unix co-creator) and Joe Condon (hardware) at Bell Labs throughout the 1970s, Belle was the first chess computer with hardware dedicated exclusively to playing: specialized circuits for move generation, position evaluation, and a transposition table implemented in microcode with alpha-beta pruning. It won the 1980 World Computer Chess Championship in Linz and five ACM North American championships. In 1983 it reached a USCF rating of 2250, becoming the first machine in history to reach Master level. Belle's architecture was used as the basis for the initial designs of ChipTest, the project that would evolve directly into IBM Deep Blue.