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There are only twelve 4x4 sudokus - and a cool trick for finding minimal subsets

The article explores the combinatorial enumeration of 4x4 Sudoku solution grids, showing there are only 12 fundamentally distinct solutions (or 288 if symmetries are counted separately). It also presents an efficient algorithmic trick for identifying minimal clue subsets that still yield a unique puzzle solution.

Background

4x4 Sudoku is a simplified variant of the classic 9x9 puzzle, often used for teaching and computational analysis due to its manageable solution space. Enumeration problems like this illustrate fundamental concepts in combinatorial search and symmetry reduction.

Source
Lobsters
Published
Sep 14, 2026 at 11:00 PM
Score
6.0 / 10