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Sudoku Solver & Generator

Master the classic logic puzzle. Play procedurally generated grids or solve any external Sudoku challenge in milliseconds.

This interactive logic tool is perfect for casual gamers looking for a mental workout or puzzle enthusiasts who need a quick solution to a difficult external grid.

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The Art of Sudoku: Strategy and Logic

Sudoku is a logic-based, combinatorial number-placement puzzle. In classic Sudoku, the objective is to fill a 9ร—9 grid with digits so that each column, each row, and each of the nine 3ร—3 subgrids that compose the grid contain all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which for a well-posed puzzle has a single solution.

Our Sudoku Solver uses a sophisticated "Backtracking Algorithm" to explore all possible combinations in milliseconds, providing the answer when logic alone becomes overwhelming.

Playing Strategies

1. Naked Singles

Scan rows and columns to find cells that can only accommodate one specific number. This is the most basic strategy for clearing easy-level puzzles.

2. Hidden Pairs

When two numbers appear as candidates in only two cells within a block, row, or column, those cells must contain those two numbers, allowing you to eliminate other candidates.

3. X-Wing

An advanced technique where candidates in a rectangular pattern across rows and columns allow for logical elimination in other sectors of the grid.

How the Solver Works

Sudoku solving is a classic example of "Constraint Satisfaction" in computer science. Every cell has constraints defined by its row, its column, and its 3x3 box. While humans use pattern recognition, our algorithm uses recursive search: it makes a guess, checks for violations, and "backtracks" if it hits a dead end. This ensures that every valid Sudoku puzzle is solvable, no matter how difficult.