even before the internetit was possible to play game of chess with someone on the other side of the world each player would set up chessboard at their home and then take turns mailing postcard to each other describing each move to do thisthe players needed way to unambiguously describe the state of the board and their moves in algebraic chess notationthe spaces on the chessboard are identified by number and letter coordinateas in figure - figure - the coordinates of chessboard in algebraic chess notation the chess pieces are identified by lettersk for kingq for queenr for rookb for bishopand for knight describing move uses the letter of the piece and the coordinates of its destination pair of these moves describes what happens in single turn (with white going first)for instancethe notation nf nc indicates that white moved knight to and black moved knight to on the second turn of the game there' bit more to algebraic notation than thisbut the point is that you can unambiguously describe game of chess without needing to be in front of chessboard your opponent can even be on the other side of the worldin factyou don' even need physical chess set if you have good memoryyou can just read the mailed chess moves and update boards you have in your imagination computers have good memories program on modern computer can easily store billions of strings like ' nf nc this is how computers can play chess without having physical chessboard they model data to represent chessboardand you can write code to work with this model this is where lists and dictionaries can come in for examplethe dictionary {' ''bking'' ''wqueen'' ''bbishop'' ''bqueen'' ''wking'could represent the chess board in figure - dictionaries and structuring data