Datasets:

Chess-Nut-Engine
/

chess-sft-corpus-4x-eval

license: apache-2.0
task_categories:
  - text-generation
language:
  - en
tags:
  - chess
  - sft
  - evaluation
  - benchmark
  - chess960
pretty_name: Chess SFT Eval and Benchmark
configs:
  - config_name: eval_splits
    data_files:
      - split: test
        path: eval_splits/*.jsonl
  - config_name: benchmark
    data_files:
      - split: test
        path: benchmark/*.jsonl
  - config_name: eval_chess960
    data_files:
      - split: test
        path: eval_splits/chess960.jsonl
  - config_name: eval_endgames
    data_files:
      - split: test
        path: eval_splits/endgames.jsonl
  - config_name: eval_evaluation
    data_files:
      - split: test
        path: eval_splits/evaluation.jsonl
  - config_name: eval_mate
    data_files:
      - split: test
        path: eval_splits/mate.jsonl
  - config_name: eval_openings
    data_files:
      - split: test
        path: eval_splits/openings.jsonl
  - config_name: eval_perception
    data_files:
      - split: test
        path: eval_splits/perception.jsonl
  - config_name: eval_planning
    data_files:
      - split: test
        path: eval_splits/planning.jsonl
  - config_name: eval_rules
    data_files:
      - split: test
        path: eval_splits/rules.jsonl
  - config_name: eval_tactics
    data_files:
      - split: test
        path: eval_splits/tactics.jsonl
  - config_name: bench_chess960
    data_files:
      - split: test
        path: benchmark/chess960.jsonl
  - config_name: bench_endgames
    data_files:
      - split: test
        path: benchmark/endgames.jsonl
  - config_name: bench_evaluation
    data_files:
      - split: test
        path: benchmark/evaluation.jsonl
  - config_name: bench_mate
    data_files:
      - split: test
        path: benchmark/mate.jsonl
  - config_name: bench_openings
    data_files:
      - split: test
        path: benchmark/openings.jsonl
  - config_name: bench_perception
    data_files:
      - split: test
        path: benchmark/perception.jsonl
  - config_name: bench_planning
    data_files:
      - split: test
        path: benchmark/planning.jsonl
  - config_name: bench_rules
    data_files:
      - split: test
        path: benchmark/rules.jsonl
  - config_name: bench_tactics
    data_files:
      - split: test
        path: benchmark/tactics.jsonl

Chess SFT Eval and Benchmark

Held-out evaluation splits and a frozen benchmark for Chess-Nut-Engine/chess-sft-corpus-4x. Every FEN in these files is excluded from generated training data (the blocklist is game-scoped: sibling positions of eval games are excluded too).

Frozen from the 4x corpus generation run of 2026-07-06 (generator revision 3cd161b1078cdfa6598fba939f40250072adb524)
Benchmark: 13,000 frozen examples across 9 splits; eval splits share the game-scoped blocklist (182,061 FENs) excluded from the training corpus


Eval examples	13,000
Benchmark examples	13,000
Format	JSONL

Loading

from datasets import load_dataset

eval_ds = load_dataset("Chess-Nut-Engine/chess-sft-corpus-4x-eval", "eval_splits")
bench_ds = load_dataset("Chess-Nut-Engine/chess-sft-corpus-4x-eval", "benchmark")

Eval Splits

Split	Description	Examples	Size
`chess960`	Fischer Random positions	500	0.1 MB
`endgames`	Tablebase-backed endgame play	1,500	0.2 MB
`evaluation`	Position assessment	1,500	0.3 MB
`mate`	MATE move-choice examples	1,000	0.1 MB
`openings`	Opening knowledge with ECO holdout	500	0.2 MB
`perception`	Board reading and representation	2,000	0.3 MB
`planning`	Best move, puzzle, and consequence tasks	2,000	1.0 MB
`rules`	Move legality and chess rules	2,000	0.3 MB
`tactics`	Tactical motifs and puzzle labels	2,000	1.0 MB

Frozen Benchmark

Split	Description	Examples	Size
`chess960`	Fischer Random positions	500	0.2 MB
`endgames`	Tablebase-backed endgame play	1,500	0.5 MB
`evaluation`	Position assessment	1,500	0.7 MB
`mate`	MATE move-choice examples	1,000	0.4 MB
`openings`	Opening knowledge with ECO holdout	500	0.3 MB
`perception`	Board reading and representation	2,000	1.5 MB
`planning`	Best move, puzzle, and consequence tasks	2,000	1.4 MB
`rules`	Move legality and chess rules	2,000	1.6 MB
`tactics`	Tactical motifs and puzzle labels	2,000	1.4 MB