AI SUDOKU
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The Sudoku Blog
The ideas behind the game — how a solver generates a puzzle that has exactly one answer, and the human logic techniques that the AI Hint engine uses to solve it.
Inside the AI
How a Sudoku Solver Works: Backtracking and Unique Solutions
Depth-first search, constraint checking, and the clever uniqueness test that guarantees every generated puzzle has exactly one solution — so you never have to guess.
Read StrategyThe Logic Techniques Behind Every Sudoku
From naked and hidden singles up to pairs, pointing pairs and the X-Wing — the deductions that turn a wall of empty cells into a fully solved grid.
Read HistoryThe History of Sudoku — From Latin Squares to a Global Craze
From Euler's Latin squares to Howard Garns' 1979 "Number Place," Nikoli naming it in Japan, and Wayne Gould's 2004 boom in The Times — how the puzzle conquered the world.
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