Sudoku: 129

: Spotting two numbers that can only go in two specific cells within a row or block, effectively "locking" them in.

If you are stuck on a Sudoku 129, draw an . Find a number that appears as a candidate in exactly two rows and two columns forming a rectangle. That number can then be eliminated from the corners of the rectangle. sudoku 129

"Sudoku 129" refers here to a single standard 9×9 Sudoku puzzle identified by the number 129 (for example in a puzzle book or online collection). It uses the usual rules: fill each row, column, and 3×3 block with digits 1–9 exactly once. : Spotting two numbers that can only go