Sudoku Solver, Difficulty & Candidate Analyzer
Analyze Sudoku puzzle difficulty based on clue count, check missing candidate digits in rows/blocks, and explore constraint satisfaction solving techniques.
Formula
Empty Cells = 81 - Clues | Candidates = {1..9} \ Present Digits
Source / method note
Based on combinatorial mathematics, constraint satisfaction, and Gary McGuire’s 17-clue minimum theorem.
Legal / official rate note
A standard 9x9 Sudoku puzzle requires at least 17 initial clues to have a unique valid solution.
Frequently Asked Questions
What is the minimum number of clues in Sudoku?
Mathematical research has proven that 17 is the absolute minimum number of clues required for a unique 9x9 Sudoku solution.
