ding targets for the value and policy heads derived from those games. AlphaZero completed its training in 9 hours using 5,000 Version-1 Tensor Processing Units (TPUs). With ChessCoach, I had free access to approximately 50 v3-8 TPUs by the end, generously provided through Google's TPU Research Cloud (TRC) program – an astonishing amount of computing power – but training still took multiple weeks for the final run, and months to reach that point. It is a little disappointing how many training games are n