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Benchmark page
Claude Haiku 4.5 scored 8.7% strict accuracy on ChessBench, solving 13 of 150 fixed Lichess tactics when the answer had to match the expected UCI move line exactly.
Strict accuracy
8.7%
Correct puzzles
13 / 150
Prompt tokens
76,316
Total cost
$0.15
Benchmark updated
Mar 24, 2026, 5:38 AM
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 Haiku 4.5chess benchmark" and "Claude Haiku 4.5tactical reasoning results".
For the full dataset definition and scoring details, visit the ChessBench dataset and methodology page.
These examples add readable, model-specific context beyond a single leaderboard number.
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Expected line: b1h7
Model line: No parseable line returned
Parse status: invalid_count
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