Lightning talk at wroclove.rb 2023 making the case that chess is a great hobby for programmers: scientific, meritocratic, with measurable progress via FIDE ratings (speaker showed his rating since 2003). Modern online play on chess.com or lichess (lichess is fully open source, written in Scala) offers post-game analysis and 'learn from your mistakes' features. Chess has historically been AI's first battlefield (Kasparov beaten in 1997, then AlphaZero). Modern chess 'engines' are neural networks; most popular open-source ones are Stockfish and Leela. Speaker recounts a recent drawn game against Grandmaster Christopher Kobojski at a tournament in Katowice, analyzed afterwards on a digital chessboard connected to a chess engine (depth 51 half-moves). Practical tips: open with E4, develop knight and bishop, castle early, control the center, avoid knights on the edge, centralize rooks. Learn 'chunks' / patterns (fianchetto, London setup). Notes event sourcing exists in chess too — chess notation is essentially an event store, storing even move timings. Encourages playing live in chess clubs (website 'Club' for Poland) or against the speaker on chess.com.