Mathematical researchers have shown that the minimum number of givens (17) applies uniquely to the standard 9×9 format.
Mathematical researchers have shown that the minimum number of givens (17) applies uniquely to the standard 9×9 format.
When you find a naked pair, check if those same two cells also form a pair in their shared column.
When you find a naked pair, check if those same two cells also form a pair in their shared column.