Sixteen months ago my CNN beat HastyBot 51.7% of the time. The new transformer value net, macondo-tf, wins 57.65% over 100,000 game pairs, level with a 2-ply Monte Carlo simulation while thinking more than a thousand times faster. Here’s everything we tried to get there, including the long list of things that didn’t work.

How we implemented mathematically rigorous Bayesian inference in Macondo to let BestBot reason about its opponent’s rack, and why it only barely edges out going first.