Coding Adventure: Making a Better Chess Bot

Sebastian Lague explains how he improved his chess engine using bitboards, search extensions, and transposition tables.

Trying to improve an old chess bot by experimenting with various interesting techniques. This is a sequel to: youtu.be/U4ogK0MIzqk Support my work (and get early access to new videos and source code) on Patreon or Nebula * Patreon: patreon.com/SebastianLague * Nebula: go.nebula.tv/sebastianlague Source code: * GitHub: github.com/SebLague/Chess-Coding-Adventure Credits and references * A really fun video about various algorithms for playing chess by @tom7: youtube.com/watch?v=DpXy041BIlA * Music and images: github.com/SebLague/Misc-Project-Info/blob/main/Coding-Adven… Chapters: 00:00 Intro 00:38 Battle of the Bots 03:18 Maybe Don’t Throw Away the Best Move? 07:13 Transposition Troubles 10:55 Search Extensions 14:01 Refactoring and Recapping 15:51 Tweaking Kings and Pawns 19:35 Bitboards! 23:54 Passed Pawns (and more) 28:32 Magic Bitboards (minus the magic) 34:40 The Magical Part of Magic Bitboards 39:00 Testing and Optimizing Move Generation 41:50 Killers, Reductions, and Repetitions 45:56 Creating a Lichess Bot 49:30 Let’s Play! 54:54 Existential Crisis 55:02 The Bot’s First Game Online 56:12 Can Our Bot Beat Stockfish? (No) 56:59 Rating Speculation 59:28 Outro