humanchess-900-1000-blitz-checkmates

HumanChess 900-1000 Blitz Checkmates

HumanChess 900-1000 Blitz Checkmates is a human-move policy model trained by imitation on Lichess blitz games where both players were rated 900-1000. The dataset includes complete games that ended in checkmate; the model itself is a policy network without search or a value head.

This release contains both the original PyTorch training checkpoint and a standalone INT8 TorchScript model optimized for x86 CPU inference.

Files

The FP32 checkpoint is about 525 MB because it includes AdamW optimizer state. Its raw model weights occupy about 175 MB. The INT8 artifact is about 44 MB.

Architecture

• CNN policy network
• 128 channels
• 6 residual blocks
• Input: 19 x 8 x 8 board tensor
• Output: fixed move-vocabulary logits, masked to legal moves at inference
• Saved epoch: 6 (best validation checkpoint)

FP32 Validation Metrics

Measured on 300,000 held-out positions:

INT8 Quantization

The INT8 model uses statically quantized x86 convolution and linear layers. On an 8,192-position comparison sample:

In a color-balanced 100-game match at temperature 0.5 with the first six plies sampled, FP32 scored 55.5% (50 wins, 39 losses, 11 draws). The estimated FP32 advantage was 38 Elo with a wide 65-Elo error margin, so the playing-strength difference was not statistically conclusive.

Inference

With the HumanChess UCI application, load the FP32 checkpoint normally:

human-chess-uci \
  --checkpoint checkpoints/cnn-128x6-900-1000-blitz-checkmates.pt \
  --device cpu

Load the standalone INT8 model with --torchscript:

human-chess-uci \
  --checkpoint artifacts/cnn-128x6-900-1000-blitz-checkmates-int8.ts \
  --torchscript \
  --device cpu

The tournament configuration used --temperature 0.5 --sample-plies 6.

Limitations

• Policy-only: no search and no value evaluation.
• Trained on a narrow rating and time-control distribution.
• The INT8 artifact is intended for x86 CPU execution.
• Tournament Elo differences are relative measurements, not an absolute human or engine rating.