---
license: mit
tags:
- chess
- puzzle
size_categories:
- 100K<n<1M
configs:
- config_name: default
  data_files:
  - split: top_row
    path: "hippodrome_solutions_og.csv"
  - split: first_column
    path: "hippodrome_solutions_first_column.csv"
  - split: last_column
    path: "hippodrome_solutions_last_column.csv"
  - split: center
    path: "hippodrome_solutions_center.csv"
  - split: corners
    path: "hippodrome_solutions_corners.csv"
---
Interactive version at https://hippodrome.onrender.com. <br>

Solutions to all [Hippodrome chess puzzles](https://www.chessvariants.org/solitaire.dir/hippodrome.html).
Hippodrome is a type of chess puzzle in which the player has to move 4 knights from the bottom row to the top row (or some designated spots) in a 4x4 grid. Solutions is generated using A* search algorithm.
Note that since there are only 1 empty spot, and no captures allowed, this essentially means that queens function effectively as kings. 

Dataset Splits
The dataset is divided into five splits based on the initial positions of the knights in the 4x4 grid. Each split contains puzzle configurations with similar structural constraints:

- top_row: All knights start in the bottom row and must reach the top row.
- first_column: Knights must reach the first column from their starting positions.
- last_column: Knights must reach the last column.
- center: Knights must occupy the central 2x2 squares of the grid.
- corners: Knights must reach the four corners of the board.

Detailed Statistics: 
| Target | Total Configurations | Unsolvable | Shortest Solution | Longest Solution | Average Moves | Median Moves |
| :--- | :--- | :--- | :--- | :--- | :--- | :--- |
| **Top Row** | 415,801 | 2,731 | 21 | 38 | 26.8 | 27 |
| **Center** | 415,801 | 2,731 | 8 | 42 | 12.4 | 11 |
| **Corners** | 415,801 | 2,738 | 10 | 24 | 13.1 | 13 |
| **First Column** | 415,801 | 2,731 | 9 | 30 | 13.5 | 13 |
| **Last Column** | 415,801 | 2,731 | 9 | 30 | 13.5 | 13 |