Evaluation symbols
Evaluation symbols
Definition
Evaluation symbols are shorthand marks appended to moves or positions in annotated chess games to convey qualitative judgments at a glance. They indicate the strength of a move (for example, brilliant, good, dubious, or a blunder) and the assessment of a position (for example, equal, slight advantage for White, or decisive advantage for Black). They complement verbal commentary and, in modern notation, can be encoded using Numeric Annotation Glyphs (NAGs) in PGN files.
How they are used in chess
Annotators place symbols immediately after moves (e.g., 24...Rxd4!!) or after a move number or position description (e.g., “Position after 15...Na5: +=”). In books, databases, and magazines, these symbols enable readers to grasp the main narrative of a game—where the turning points and instructive moments occurred—without reading long prose. Engines and databases often translate between human-friendly symbols and internal NAG codes.
Common symbols and meanings
- Move quality:
- ! — good move
- !! — brilliant or exceptional move
- !? — interesting, practical, or speculative move
- ?! — dubious or risky move
- ? — mistake
- ?? — blunder
- Only move — sometimes noted as “only move” or with a special glyph in databases; indicates a unique move to avoid disadvantage
- Position evaluation:
- = — equal
- += or ⩲ — slight advantage for White
- =+ or ⩱ — slight advantage for Black
- +− or ± — clear/decisive advantage for White
- −+ or ∓ — clear/decisive advantage for Black
- ∞ — unclear/complicated position
- ⟂ or “comp” — compensation (often used in text) for material
- “with initiative” — sometimes marked by a dedicated glyph in Informant-style notation, or written out
Notes on typography: Some sources prefer “+−” and “−+” instead of “±” and “∓” to avoid font ambiguity. The Informant system also includes symbols for attack, counterplay, zugzwang, passed pawns, bishops vs knights, and many other thematic concepts; in general-purpose annotations, the compact set above is most common.
Examples
- Brilliancy (!!):
Kasparov vs. Topalov, Wijk aan Zee 1999: In a famous attacking sequence, Black uncorked 24...Rxd4!!, a stunning exchange sacrifice that initiated a winning king hunt. Annotators universally mark this move with “!!” to signal its depth and audacity.
- Blunder (??):
Kramnik vs. Deep Fritz, Bonn 2006 (Game 2): In a balanced position, 34...Qe3?? walked into a forcing mate, and the engine replied 35. Qh7#. Double-question marks highlight the decisive tactical oversight.
- Speculative idea (!?):
1. e4 c5 2. b4!? (Wing Gambit): Often annotated “!?” to show it’s playable and ambitious, trading material and structure for rapid development and initiative.
- Dubious decision (?!):
In the Ruy Lopez: 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O Nxe4?! — Accepting the center pawn at once is risky; theoretical lines suggest Black faces unpleasant pressure after 5. Re1. The “?!” warns that practical difficulties outweigh the material gain.
- Position evaluations after a sequence:
Najdorf-type middlegame: 1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bg5 e6 7. f4 Be7 8. Qf3 Qc7. Many sources give “∞” (unclear) or balanced symbols depending on taste and engine depth, indicating that dynamic chances exist for both sides.
Endgame edge: In a rook-and-pawn endgame where White’s rook is active behind a passed a-pawn and kings are centralized, annotators may summarize: “+= with the more active rook; converting requires precision.”
Strategic and historical significance
Evaluation symbols evolved to compress rich chess ideas into a universally readable language. Classic annotators like Steinitz, Lasker, and Alekhine used “!” and “?” to teach pattern recognition and critical moments. In the 1960s, Chess Informant standardized an expansive iconography covering themes such as initiative, attack, counterplay, and positional features, influencing generations of players and shaping how theory is communicated.
With the advent of chess engines, numeric evaluations (e.g., +1.20) became ubiquitous. Still, symbolic annotations remain vital: “!?” or “+=” conveys practical and strategic context that a raw number cannot—how hard a position is to play, what the long-term trumps are, and where the human decision points lie.
Working with engines and symbols together
- Translate thoughtfully: As a rough guide, “+=” often corresponds to a small numerical edge (about +0.30 to +0.70 for White), while “±/+-” suggests a much larger, often winning advantage. Context matters: a +0.70 in a simple endgame is more meaningful than +0.70 in a razor-sharp middlegame.
- Be consistent: Pick either “±/∓” or “+−/−+” and stick to it. Likewise, use “!?” and “?!” consistently to differentiate practical chances from dubiousness.
- Explain critical moments: Use symbols to flag key decisions, then add a short verbal note (e.g., “?! — weakens dark squares”) so readers learn the underlying idea.
Encoding in PGN (NAGs)
PGN supports Numeric Annotation Glyphs that encode these symbols (e.g., $1 for “!”, $2 for “?”, etc.). Chess software displays them as human-readable symbols. While exact mappings vary across extended sets, most tools reliably support the core move-quality and positional-evaluation glyphs. If a viewer shows “$1” instead of “!”, it likely lacks full NAG support or needs a font update.
Interesting facts and anecdotes
- Brilliancy prizes: Before engines were widespread, tournament brilliancy prizes often spotlighted “!!” moves—memorable tactical ideas that still inspire players today.
- Editor’s voice: Some annotators are sparing with “!!” and “??” to avoid inflation, while others use them liberally to keep commentary lively. Recognizing an annotator’s “dial” helps you interpret their evaluations.
- Informant language: For decades, top players communicated opening novelties using Informant symbols and ECO codes, enabling a language-neutral, global theory exchange long before online databases.