If you are stuck on a difficult 129-level puzzle, standard scanning might not be enough. Professional solvers use these expert maneuvers:
Thorne frowned. He looked at the clues the newspaper provided. There was no '1', '2', or '9' given in the first column. He must have filled them in during his initial scan. sudoku 129
Start by looking for rows, columns, or 3x3 boxes that are nearly full. If a box has 8 cells filled, the 9th is forced. This is the fastest way to get your initial numbers down. 3. Pencil Marking (Candidates) If you are stuck on a difficult 129-level
: If the cell in Row 1, Column 1 contains a 4 , then the number 1 must be placed in Column 4 of that same row. Solving Techniques There was no '1', '2', or '9' given in the first column
And in the center square, in his own jagged handwriting, too small to be seen unless you were looking for it, was a tiny, microscopic row of numbers.