Mate in 1
Benchmark page
Claude Fable 5 scored 46.0% strict accuracy on ChessBench, solving 69 of 150 fixed Lichess tactics when the answer had to match the expected UCI move line exactly.
Strict accuracy
46.0%
Correct puzzles
69 / 150
Prompt tokens
110,199
Total cost
$14.40
Benchmark updated
Jun 9, 2026, 6:11 PM
Find the tactical line that creates a fork.
Find the line that wins an undefended piece.
Solve a forced mate in one move.
Solve a forced mate in two moves.
Find the tactical line that exploits a pin.
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It also links back to the benchmark methodology and exposes model-specific copy, numbers, and sample puzzle outcomes that are relevant to searches like "Claude Fable 5chess benchmark" and "Claude Fable 5tactical reasoning results".
For the full dataset definition and scoring details, visit the ChessBench dataset and methodology page.
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Expected line: g8h7
Model line: No parseable line returned
Parse status: missing
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