Difference between revisions of "Sudoku-X"
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'''Sudoku-X''' is | '''Sudoku-X''' is a well known [[Sudoku Variant]]. It is similar to a standard [[Sudoku]], but both [[diagonal]]s must also contain digits 1 through 9. | ||
Because the diagonals significantly reduce the number of [[Unavoidable Set]]s, the puzzle can contain less [[given]]s than a standard Sudoku. Also, the diagonals create opportunities for additional [[ | Because the diagonals significantly reduce the number of [[Unavoidable Set]]s, the puzzle can contain less [[given]]s than a standard Sudoku. Also, the diagonals create opportunities for additional [[solving technique]]s, such as [[Skewed Fish]] ([[Triangular Connection]], [[Crossover]], [[Double Crossover]], [[Finned Double Crossover]], [[Skewed Swordfish]]), [[Multiple Crossover]], [[Weak Link Square]] and [[Skewed XY-Wing]]. | ||
The diagonal [[constraint]]s are also used in several other variants and sizes. For example, the [[Killer]] variant can be combined with diagonal constraints to form Killer-X. A more extreme example would be [[Clueless]]-[[Shaolin]]-X. | The diagonal [[constraint]]s are also used in several other variants and sizes. For example, the [[Killer Sudoku]] variant can be combined with diagonal constraints to form [[Killer-X]]. A more extreme example would be [[Clueless]]-[[Shaolin]]-X. | ||
Below is one easy Sudoku-X puzzle. It requires only [[single]]s and one application of [[Naked Pair]]. | Below is one easy Sudoku-X puzzle. It requires only [[single]]s and one application of [[Naked Pair]]. | ||
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[[Category:Sudoku-X]] | [[Category:Sudoku-X]] | ||
[[Category:Sudoku Variants]] | |||
Latest revision as of 10:42, 30 October 2021
Sudoku-X is a well known Sudoku Variant. It is similar to a standard Sudoku, but both diagonals must also contain digits 1 through 9.
Because the diagonals significantly reduce the number of Unavoidable Sets, the puzzle can contain less givens than a standard Sudoku. Also, the diagonals create opportunities for additional solving techniques, such as Skewed Fish (Triangular Connection, Crossover, Double Crossover, Finned Double Crossover, Skewed Swordfish), Multiple Crossover, Weak Link Square and Skewed XY-Wing.
The diagonal constraints are also used in several other variants and sizes. For example, the Killer Sudoku variant can be combined with diagonal constraints to form Killer-X. A more extreme example would be Clueless-Shaolin-X.
Below is one easy Sudoku-X puzzle. It requires only singles and one application of Naked Pair.
Minimum Number of Givens
Ruud has a collection of Sudoku-X puzzles with as few as 12 givens. However, the actual minimum number of givens required for a valid Sudoku-X puzzle is not known.
