---
license: cc0-1.0
tags:
- chess
- lichess
- stockfish
---
# Dataset Card for the Stockfish Evaluations

A dataset of chess positions evaluated with various flavours of Stockfish running within user browsers. Produced by, and for, the [Lichess analysis board](https://lichess.org/analysis). Evaluations are formatted as JSON; one position per line. 

The schema of a position looks like this:

```
{
  "fen": "8/8/2B2k2/p4p2/5P1p/Pb6/1P3KP1/8 w - -",
  "depth": 42,
  "evaluation": 5.64,
  "best_move": "Kg1",
  "best_line": "Kg1 Ke6 Kh2 Kd6 Be8 Kc5 Kh3 Kd6 Bb5 Ke7"
}
```

- **`fen`**: `string`, the position FEN only contains pieces, active color, castling rights, and en passant square.
- **`depth`**: `int`, the depth reached by the engine.
- **`evaluation`**: `string`, the evaluation for the given FEN/board state.
- **`best_move`**: `string`, the first move of the best_line, in **SAN** format.
- **`best_line`**: `string`, the first principal variation for the given highest available depth, in **SAN** format.