2016-11-04-chess-research.md

Demo of interacting with stockfish.js engine - https://chrisroos.github.io/upgraded-waddle/?#.

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Stockfish

• Command line chess engine
• Using it from the command line
• GUIs communicate using UCI
• stockfish.js

Glossary

• UCI - Universal Chess Interface
• Opening Book - Set of initial moves in a game of chess
  • White - move first
  • Black - move second
• Ply

  • In two-player sequential games, a ply refers to one turn taken by one of the players.

Board layout

8 |__|__|__|__|__|__|__|__|
7 |__|__|__|__|__|__|__|__|
6 |__|__|__|__|__|__|__|__|
5 |__|__|__|__|__|__|__|__|
4 |__|__|__|__|__|__|__|__|
3 |__|__|__|__|__|__|__|__|
2 |__|__|__|__|__|__|__|__|
1 |__|__|__|__|__|__|__|__|
   a  b  c  d  e  f  g  h

FEN

Example: "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"

Note. This is the standard start position of the board

• Field 1 - state of the board
  • row 1 - black - rook, knight, bishop, queen, king, bishop, knight, rook
  • row 2 - black - 8 pawns
  • row 3 - 8 empty squares
  • row 4 - 8 empty squares
  • row 5 - 8 empty squares
  • row 6 - 8 empty squares
  • row 7 - white - 8 pawns
  • row 8 - white - rook, knight, bishop, queen, king, bishop, knight, rook
• Field 2 - next move by "w"hite or "b"lack
• Field 3 - Castling ability
  • K - white can castle kingside
  • Q - white can castle queenside
  • k - black can castle kingside
  • q - black can castle queenside
• Field 4 - En passant target square
  • "-" = no en passant target square
• Field 5 - Halfmove clock
  • Number of halfmoves since the last capture or pawn advance
• Field 6 - Fullmove number
  • The number of the full move. It starts at 1, and is incremented after Black's move

UCI

• Protocol can be downloaded from http://www.shredderchess.com/download.html
• UCI is stateless
  • State of board must be submitted as FEN or as a series of moves from the start position
• Using score to get idea of who is winning
  • Contains information about how to interpret the scores from Stockfish

Setting position

• Using FEN (Forsyth-Edwards Notation)
  • Example: "position fen rnbqkbnr/pp1ppppp/8/2p5/4P3/5N2/PPPP1PPP/RNBQKB1R b KQkq - 1 2"
    • Use http://www.chess-poster.com/english/fen/fen_epd_viewer.htm to view this board
• Using moves from start position
  • Example: "position startpos moves e2e4 e7e5"
    • White pawn ends up at e4
    • Black pawn ends up at e5
  • This appears to be using the Algebraic notation

Scoring

• UCI scoring
  • Chess engines appear to return score relative to player about to move
    • http://support.stockfishchess.org/discussions/questions/1332-interpreting-stockfish-outputs
• Centipawns
  • Positive value is white advantage
  • Negative value is black advantage
• Analysing scores from Stockfish blog post

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• James
  • How to determine current state of play - hardware or image recognition
• Chris
  • Stockfish (or similar) to understand current state of the game
• Ben
  • Generative music