Sudoku Expert Guide: X-Wing, Swordfish, XY-Wing and Forcing Chains Explained
Plus Expert sudoku puzzles are the ones where basic scanning stops working on the 9×9 grid. Naked singles dry up, hidden singles hide, and the grid just sits there. Solving at…
swordfish sudoku
Swordfish Sudoku: The Advanced 3×3 Technique Explained
The Swordfish is an advanced sudoku technique where a single candidate digit is confined to the same three columns across three rows (or vice versa), letting you eliminate that digit…
Extreme Sudoku: The Hardest Difficulty Level Explained
Extreme Sudoku is the hardest named difficulty level of 9×9 Sudoku offered on many puzzle sites, sitting above easy, medium, hard and evil. These puzzles give you very few starting…