---
license: cc0-1.0
pretty_name: Antichess Openings
tags:
- chess
- lichess
- game
- games
dataset_info:
  features:
  - name: name
    dtype: string
  - name: pgn
    dtype: string
  - name: uci
    dtype: string
  - name: epd
    dtype: string
  - name: result
    dtype: string
  splits:
  - name: train
    num_bytes: 50493
    num_examples: 334
  download_size: 17073
  dataset_size: 50493
configs:
- config_name: default
  data_files:
  - split: train
    path: data/train-*
---

# Dataset Card for Lichess Antichess Openings

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

A list of 334 documented Antichess openings.

### Antichess rules

[Antichess](https://lichess.org/variant/antichess) is an eccentric variant where you lose all your pieces or get stalemated to win. Pieces move the same way they do in standard chess; however, kings lose their royal powers - they cannot castle, and checks are no longer a threat. Since kings have lost their royal powers, pawns may be promoted to kings.
Capturing is forced. If you can take a piece, you must. If multiple pieces can be captured, you may choose which piece you capture. To compensate for the nature of Antichess, you will always be given a chance to decide for promotions, even if you have enabled the option to always promote to Queens.



### Dataset Creation

The data for this dataset was manually curated by **[tolius](https://lichess.org/@/tolius)**.

### Dataset Usage

Using the `datasets` library:

```python
from datasets import load_dataset

dset = load_dataset("Lichess/antichess-chess-openings", split="train")
```
 Using the `pandas` library:

 ```python
import pandas as pd

df = pd.read_parquet("hf://datasets/Lichess/antichess-chess-openings/data/train-00000-of-00001.parquet")
```

Using the `polars` library:

```python
import polars as pl

df = pl.read_parquet('hf://datasets/Lichess/antichess-chess-openings/data/train-00000-of-00001.parquet')
```

## Dataset Details

### Dataset Sample

One row of the dataset looks like this:

```python
{
 'name': 
 'pgn': 
 'uci': 
 'epd':
}
```
### Dataset Fields

Every row of the dataset contains the following fields:

- **`name`**: `string`, the name of the opening in English.
- **`pgn`**: `int`, the sequence of moves leading to the opening position. If not unique, the moves are the most common ones leading to that opening.
- **`uci`**: `int`, the same moves described by the `pgn` field in [UCI notation](https://backscattering.de/chess/uci/#move).
- **`epd`**: `int`, the [EPD](https://www.chessprogramming.org/Extended_Position_Description) ([FEN](https://en.wikipedia.org/wiki/Forsyth%E2%80%93Edwards_Notation) without move numbers) of the opening position, en passant field only if legal

### Dataset Conventions

* Title case is used for opening names.
* Names are structured like `Opening family: Variation, Subvariation, ...`,
  e.g., `Sicilian Defense: Najdorf Variation, English Attack`.
* The suggested way to classify games is to play moves backwards until
  a named position is found. To make this work well with common transpositions,
  multiple entries for a single opening may be added.
* However, each name has a unique *shortest* line. If necessary,
  a distinguishing move is appended, e.g.,
  `King's Gambit Accepted: Schurig Gambit, with Bb5`.

## Additional Information

- To contribute to the dataset, send a PR or open a discussion in the [community tab](https://huggingface.co/datasets/Lichess/antichess-chess-openings/discussions).