Alpha-Beta

two chess projects live in this codebase, and honesty requires separating them up front. the first is a from-scratch javascript engine (in arcade/references/chess/js/, built following the classic bluefever software series): 120-square mailbox board, hand-rolled move generator validated by perft, material + piece-square evaluation, alpha-beta with quiescence, a principal-variation hash table, and iterative deepening. the second is voice chess (code/private/chess-bot/, published as github.com/abaj8494/ollama-voice-chess): there i did not write the engine — stockfish plays the moves over uci — and the engineering is in the wrapper: skill throttling, an ollama llm that provides spoken commentary without being allowed to hallucinate moves, neural tts, and spaced-repetition opening training. one project teaches you how engines work; the other teaches you what to build around an engine. 𐃏

ordinary tic-tac-toe is a solved bore — both players draw with a lookup table. glue nine boards together and add one rule about where you are allowed to move, and suddenly the game tree is deep enough that you need actual search theory: minimax, the negamax reformulation, alpha-beta pruning, and a heuristic to stand in for the leaves you cannot reach. this page documents the agent my partner and i wrote for unsw comp3411 (assignment 3, “nine-board tic-tac-toe”), warts and all — and the warts are instructive. 𐃏