Analysis glossary

Accuracy — A 0–100% summary of how well a player’s moves preserved the chances Stockfish saw. See Accuracy and CPL.

CPL (centipawn loss) — The estimated amount of evaluation given up on one move. One centipawn is one hundredth of a pawn in the engine’s scoring system. Lower is usually better. See Accuracy and CPL.

Depth — How far ahead Stockfish searched along a line, counted in half-moves. More depth can reveal ideas that a shorter search misses.

DTZ / DTM — Tablebase distances in half-moves: distance to zeroing (a pawn move, capture, or mate) and distance to mate. Continuation badges describe the position after the listed move. See Syzygy endgame tablebases.

Tablebase — Precomputed endgame results for covered positions. Ironwood’s Syzygy tab supports standard positions with seven pieces or fewer and no castling rights. See Syzygy endgame tablebases.

Evaluation (eval) — Stockfish’s estimate of who stands better. Positive favors White; negative favors Black. See Evaluation and the graph.

Elo — A rating system based on results against other rated players. See What is Elo?.

FEN — A compact text description of one chess position, including whose turn it is. It records a position, not the history of a whole game. See What is FEN?.

FICS — The Free Internet Chess Server, which Ironwood can connect to for online games.

Hash — Engine memory used to remember positions it has already searched.

MultiPV — Multiple principal variations: several candidate engine lines shown together. See Best move and engine line.

NNUE — A type of neural-network evaluation used by Stockfish to judge positions. The engine still searches possible moves; NNUE helps it estimate how promising positions are.

Nodes — Chess positions examined by the engine during a search.

NPS (nodes per second) — How quickly the engine is examining positions on your device.

PGN — Portable Game Notation, a text format for a game’s moves and optional annotations. See What is PGN?.

PV (principal variation) — The engine’s current sample line of strong moves for both sides. See Best move and engine line.

SAN — Standard Algebraic Notation, the familiar short chess move format such as Nf3 for a knight move to f3. See How to read chess moves.

Move symbols — Ironwood uses ★ for Best, + for Good, ?! for Inaccuracy, ? for Mistake, and ?? for Blunder. See What do the move symbols mean?.

UCI move — A coordinate form of a move used by chess software, such as g1f3 for a move from g1 to f3.

Verification — Ironwood’s deeper second look at positions around moves that may have changed the game. See Game phases and critical moves.