SakanaAI/sudoku-bench-nikoli

Sudoku-Bench: nikoli_100

🐙 [Sudoku-Bench GitHub]
📝 [Technical Report]

The Sudoku-Bench project has been discontinued. The nikoli_100 puzzle collection remains available for download here.

Dataset description

The nikoli_100 dataset contains 100 beautiful handmade standard Sudoku puzzles designed by Nikoli, the Japanese puzzle company that popularized Sudoku in the 1980s. The collection was curated in partnership with Nikoli as part of Sudoku-Bench, a benchmark for evaluating the reasoning capabilities of large language models.

Algorithmically generated Sudoku puzzles tend to find only puzzles of a certain type, namely whose solution path is similarly algorithmic. Human setters are more capable of creating puzzles that require deeper reasoning and creativity in the solve: see this video for an example.

Quickstart

import datasets

nikoli_100 = datasets.load_dataset("SakanaAI/sudoku-bench-nikoli", split="test")

Puzzle fields

Each puzzle contains the fields:

• puzzle_id: Identifier for the puzzle
• sudokupad_url: Link to play the puzzle on SudokuPad
• author: Creator of the puzzle (Nikoli for all puzzles in this collection)
• title: Name of the puzzle
• rules: The puzzle rules (standard 9×9 Sudoku rules for all puzzles in this collection)
• initial_board: 81-character string representation of the starting grid in row-major order, with empty cells shown as .
• solution: 81-character string representation of the completed grid
• rows: Number of rows in the puzzle (always 9)
• cols: Number of columns in the puzzle (always 9)
• visual_elements: JSON-encoded string describing visual components for Sudoku variants. All puzzles in this collection are standard Sudoku, so this field is always the empty list []
• encoded_puzzle: A compressed representation of the puzzle using SudokuPad's encoding scheme. https://sudokupad.app/{encoded_puzzle} loads the puzzle in SudokuPad without a call to the SudokuPad puzzle database

Example puzzle

The first puzzle in the dataset:

• puzzle_id: 'nhk2212m'
• sudokupad_url: 'https://sudokupad.app/u3hluueg8w'
• author: 'Nikoli'
• title: 'Nikoli nhk2212m'
• rules: '"Normal 9x9 sudoku rules apply."'
• initial_board: '7..6....8...9..5....6.4..3.23...8.....4...6.....7...91.2..3.4....1..9...8....1..'
• solution: '74561392831298754698654213723916875417439568265872439152783641946125987389347126'
• rows: 9
• cols: 9
• visual_elements: '[]'
• encoded_puzzle: 'sclN4SwJgXA5AdgFgawExIIxILZQDQYKYAuAhmEcRMEQK4FwD2ATtAHIgJ...' (truncated)

License and attribution

This dataset is released under the CC BY 4.0 license. Please credit Nikoli when using these puzzles.

We are grateful to Nikoli for curating the nikoli_100 collection.

Citation

@misc{seely2025sudoku,
      title={Sudoku-Bench: Evaluating creative reasoning with Sudoku variants},
      author={Jeffrey Seely and Yuki Imajuku and Tianyu Zhao and Edoardo Cetin and Llion Jones},
      year={2025},
      eprint={2505.16135},
      archivePrefix={arXiv},
      primaryClass={cs.AI},
      url={https://arxiv.org/abs/2505.16135},
}