Everyone says a minimax Tic-Tac-Toe bot is "unbeatable." I wanted a number instead of a vibe — so I benchmarked the exact engine that ships in my game. The code and the harness are open source; every figure below reproduces with node benchmark.js.
Three things I measured: whether it can actually lose, how much alpha-beta pruning really saves, and whether bigger boards crack it.
1. The proof isn't a sample — it's the whole game tree
On a 3×3 board, Hard mode runs a full depth-9 minimax search, so its reply to any position is deterministic. That means I don't have to sample games — I can enumerate every reachable one: every move a human could make, answered by the AI.
Playing second, exactly as it does in the game:
