---
dataset_info:
  features:
  - name: text
    dtype: string
  - name: players
    dtype: string
  - name: num_moves
    dtype: int16
  - name: n_passes
    dtype: int16
  splits:
  - name: train
    num_bytes: 6197484135
    num_examples: 20000000
  - name: test
    num_bytes: 1176312920
    num_examples: 3796010
  download_size: 2805767980
  dataset_size: 7373797055
configs:
- config_name: default
  data_files:
  - split: train
    path: data/train-*
  - split: test
    path: data/test-*
---
# Othello (synthetic)

Uniformly-random **legal Othello** games -- a regeneration of the synthetic training data from [*Emergent World Representations: Exploring a Sequence Model Trained on a Synthetic Task*](https://arxiv.org/abs/2210.13382) (Li et al., ICLR 2023), at the paper's own scale, since the original Google Drive release is no longer reachable.

Games are generated by the **original** Othello engine from [likenneth/othello_world](https://github.com/likenneth/othello_world) (vendored in this repo under `third_party/othello_world/`), driven by `data/othello_game.py`, which seeds each game by index so the dataset is reproducible and the multiprocessing workers stay independent.

## The game

- Standard 8x8 Othello: four discs pre-placed in the centre, **Black moves first**, a move must bracket at least one contiguous line of opponent discs (in any of the 8 directions) between the new disc and one of your own, and every bracketed line flips.
- **Every move here is legal but otherwise random** -- uniform over the legal moves at each position. No strategy, no engine, no human games.
- **Passing.** A player with no legal move passes and the opponent moves again, so the colours in a game do **not** strictly alternate. Never infer the mover from the move index -- use the `players` column.
- A game ends when neither player can move, which is a full board (60 moves) or, occasionally, 59.

## Notation

Cells use the upstream repo's own string form (`permit_reverse`): a lowercase **row letter `a`-`h`** followed by a **column digit `1`-`8`**, e.g. `d5`, with flat board index `row * 8 + col`. Note the row comes first, which is transposed relative to standard Othello notation; it is kept so cell names, board indices and Li et al.'s own evaluation code line up without a translation layer.

## Columns

- **`text`** — the moves in play order, comma separated, e.g. `f5, f4, c3, ...`. The number of moves is the game's *decision-point* count.
- **`players`** — the colour that played each move, as a string of `B`/`W` of the same length, e.g. `BWBWWB...`. A repeated letter marks a pass by the other colour.
- **`num_moves`** — decision points in the game (59 or 60).
- **`n_passes`** — how many moves were reached because the other colour had to pass.

## Splits

| Split | Games | Decision points | Avg moves/game | Games with a pass | Passes |
|---|---:|---:|---:|---:|---:|
| `train` | 20,000,000 | 1,199,496,827 | 59.97 | 6,889,947 (34.4%) | 8,924,951 (0.74%) |
| `test` | 3,796,010 | 227,670,564 | 59.98 | 1,308,791 (34.5%) | 1,696,278 (0.75%) |

Split sizes are the paper's own (20,000,000 train, 3,796,010 validation). The two splits are disjoint by construction: train draws seeds from 0 upward, `test` from 1,000,000,000 upward, and games are deduplicated by move sequence across both.

## Usage

```python
from datasets import load_dataset
ds = load_dataset("cfierro/othello-synthetic")
game = ds["train"][0]
moves = [m.strip() for m in game["text"].split(",")]
colors = list(game["players"])   # "B"/"W" per move
```

Board state, legal moves and per-position replay: `data/othello_game.py` (`decision_points`, `render`).

## Provenance

- **Code**: generated with [`data/push_othello_dataset.py` @ `8bc64a1c1e`](https://github.com/constanzafierro/rules-learning/blob/8bc64a1c1eca92528038b359fa15dfa6db753c30/data/push_othello_dataset.py).
> ⚠️ The working tree had **uncommitted changes** when this dataset was generated, so the linked commit may not exactly match the code that ran. Commit the generator before generating for a faithful link.

- **Built**: 2026-08-05T18:40:22
- **Command**:

```bash
python data/push_othello_dataset.py --out_dir /projects/nlp/data/constanzam/knowledge-ft/othello_gen_games --num_proc 64
```

- **Resolved arguments**:

```json
{
  "repo": "cfierro/othello-synthetic",
  "out_dir": "/projects/nlp/data/constanzam/knowledge-ft/othello_gen_games",
  "train_games": 20000000,
  "test_games": 3796010,
  "test_seed_offset": 1000000000,
  "num_proc": 64,
  "no_dedup": false,
  "skip_push": false,
  "push_only": false,
  "dry_run": false,
  "private": false
}
```