Chessigma

Ask Claude about chess openings, positions, games, puzzles and ratings. Every tool is read-only and needs no account. Opening guides: name an opening, such as the Sicilian Defense, Caro-Kann, London System, Queen's Gambit, Italian Game, Ruy Lopez, French Defense or King's Indian Defense, and get Chessigma's guide: the main line, up to four key variations with the idea behind each, the strategy for White and for Black, strengths and weaknesses. Popular openings have a full guide; any of about 3,700 named lines returns its name, ECO code and moves. What opening is this? Paste moves or a PGN to get the opening's name and ECO code, how far it followed known theory and the first move that left it. Positions and games: give a FEN to get the side to move, whether it is check, checkmate or stalemate, every legal move and the material count. Paste a PGN for a summary of the players, the result, the opening and how the game ended. Share a Chess.com live game or Lichess game link to get a link to its move-by-move review on chessigma.com. Daily chess puzzle: get today's puzzle, or any day's since 1 January 2024, with its position, rating and side to move, and solve it in the chat. Elo calculator: estimate a rating change after one game with the Elo formula, with K-factor defaults for FIDE, Chess.com and Lichess. Chess.com and Lichess use Glicko ratings, so their real changes differ. The tools do not run a chess engine. They state facts from the rules of chess, an opening catalogue and Chessigma's puzzle archive. For engine analysis, answers link to the Chessigma analysis board, where Stockfish runs in the browser.