PlaySudoku.us
Expert · Puzzle #464
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2
X-Wing: if a digit appears in exactly two cells in two rows, and those cells share the same two columns, eliminate that digit from those columns elsewhere.
X-Wing: if a digit appears in exactly two cells in two rows, and those cells share the same two columns, eliminate that digit from those columns elsewhere.
A Sudoku grid can be solved using only row and column logic, never needing box constraints — but it becomes exponentially harder.
A Sudoku grid can be solved using only row and column logic, never needing box constraints — but it becomes exponentially harder.