coryvegan/chess-position-evaluations

---
license: cc0-1.0
size_categories:
- 100M<n<1B
dataset_info:
features:
- name: fen
dtype: string
- name: line
dtype: string
- name: depth
dtype: uint8
- name: knodes
dtype: int32
- name: cp
dtype: int16
- name: mate
dtype: int8
splits:
- name: train
num_bytes: 97316209299
num_examples: 844812067
download_size: 40612747732
dataset_size: 97316209299
configs:
- config_name: default
data_files:
- split: train
path: data/train-*
tags:
- chess
- stockfish
- lichess
- games
---
# Dataset Card for the Lichess Evaluations dataset

<!-- Provide a quick summary of the dataset. -->
## Dataset Description

**342,059,879 chess positions** evaluated with Stockfish at various depths and node count. Produced by, and for, the [Lichess analysis board](https://lichess.org/analysis), running various flavours of Stockfish within user browsers. This version of the dataset is a de-normalized version of [the original dataset](https://database.lichess.org/#evals) and contains **844,812,067 rows**.

This dataset is updated monthly, and was last updated on January 6th, 2026.

### Dataset Usage

Using the `datasets` library:

```python
from datasets import load_dataset
dset = load_dataset("Lichess/chess-evaluations", split="train")
```

## Dataset Details

### Dataset Sample

One row of the dataset looks like this:

```python
{
"fen": "2bq1rk1/pr3ppn/1p2p3/7P/2pP1B1P/2P5/PPQ2PB1/R3R1K1 w - -",
"line": "g2e4 f7f5 e4b7 c8b7 f2f3 b7f3 e1e6 d8h4 c2h2 h4g4",
"depth": 36,
"knodes": 206765,
"cp": 311,
"mate": None
}
```

### Dataset Fields

Every row of the dataset contains the following fields:

- **`fen`**: `string`, the position FEN only contains pieces, active color, castling rights, and en passant square.
- **`line`**: `string`, the principal variation, in UCI format.
- **`depth`**: `string`, the depth reached by the engine.
- **`knodes`**: `int`, the number of kilo-nodes searched by the engine.
- **`cp`**: `int`, the position's centipawn evaluation. This is `None` if mate is certain.
- **`mate`**: `int`, the position's mate evaluation. This is `None` if mate is not certain.