license: cc0-1.0
language: en
pretty_name: ChessModel-XPU formal teacher dataset
tags:
- chess
- alphazero
- stockfish
- knowledge-distillation
- game
- reinforcement-learning
size_categories:
- 1M<n<10M
ChessModel-XPU formal teacher dataset
Stockfish-18-labeled chess positions used to train the
jinshuoli/chessmodel checkpoint,
part of the ChessModel-XPU project.
It is a custom-format dataset of bit-packed board tensors plus sparse
Stockfish-derived policy / WDL targets. It is not loadable with
datasets.load_dataset(...); use the project's TeacherDataset loader (see
below). Game-level train/validation split — adjacent positions from the same game
are never spread across splits.
Source and provenance
| Source games | Lichess Elite database, December 2023 (lichess_elite_2023-12), licensed CC0 1.0 |
| Source SHA-256 | a6a5a8253cf357d31b7b5c1895a63dfbf64cc93b4504398f748cb69a31c0eff0 |
| Teacher | Stockfish 18 — MultiPV 8, 10000 nodes/position, WDL enabled, temperature 0.15 |
| Split | Deterministic game-level 90 / 10 split, seed 7, minimum 16 plies per game |
| Prep script | scripts/prepare_formal_pgn.py |
Preparation removed parse failures, non-standard start positions, games without a decisive/draw result, short games (< 16 plies), and duplicate move sequences, then made the deterministic game-level split.
Contents
The dataset mirrors the repository layout, so downloading it into a clone of the project makes the workflow commands resolve unchanged:
| Path | Description |
|---|---|
data/formal_1m_train/shard-00000…00244.npz |
245 training shards |
data/formal_50k_validation/shard-*.npz |
13 validation shards |
datasets/formal_train.pgn |
Source training PGN (game-level split) |
datasets/formal_validation.pgn |
Source validation PGN (game-level split) |
datasets/formal_pgn_metadata.json |
Provenance metadata (source hash, counts, split params) |
Total ≈ 370 MB.
Statistics
From datasets/formal_pgn_metadata.json:
| Parsed games | 315,135 |
| Accepted games | 312,603 |
| Train / validation games | 281,003 / 31,600 |
| Train / validation positions | 2,971,862 / 334,836 |
| Validation percent | 10 |
| Seed | 7 |
Shard format
Each .npz shard is a project-defined record containing:
- Bit-packed board planes (
112 × 8 × 8, canonically oriented to the side to move: up to 8 history frames, castling rights, en-passant, side to move, halfmove and fullmove clocks). - Sparse policy target over the AlphaZero
8×8×73 = 4672move encoding. - Win/Draw/Loss target derived from Stockfish WDL.
- A shard format version, per-shard SHA-256 integrity check, Stockfish/node metadata, and the FEN (for legal-move masking and audit).
TeacherDataset loads each shard's bit-packed boards and sparse targets once and
unpacks lazily, so the full million-position dataset stays out of resident memory.
How to load
Clone the repo and download the dataset into it, then use the project loader:
git clone https://github.com/JinShuo-Li/ChessModel.git
cd ChessModel
hf download jinshuoli/chessmodel-data --repo-type dataset --local-dir .
from torch.utils.data import DataLoader
from chess_ai.data.dataset import TeacherDataset
train = TeacherDataset("data/formal_1m_train") # 245 shards
val = TeacherDataset("data/formal_50k_validation") # 13 shards
loader = DataLoader(train, batch_size=512, shuffle=True)
Verify integrity with the project's verifier:
python scripts/verify_teacher_dataset.py --dataset data/formal_1m_train
python scripts/verify_teacher_dataset.py --dataset data/formal_50k_validation
Intended use and limitations
- Intended: training / evaluating compact neural chess models via Stockfish distillation, and reproducing the project's training pipeline.
- Custom format: not consumable by the HF dataset viewer or
datasets.load_dataset(); requires the project's loader. - Labels are Stockfish outputs: policy/WDL targets reflect Stockfish 18 search at the configured node budget, not human game outcomes (game results are used only for splitting/filtering).
License and attribution
- Source game data: © Lichess, CC0 1.0 (public domain).
- The loading code and preparation scripts are MIT-licensed in the source repository.
- Stockfish is used solely as a teacher/labeling tool and is not distributed here.
Related
- Trained checkpoint:
jinshuoli/chessmodel - Source code & documentation: github.com/JinShuo-Li/ChessModel