__exclusive__: Sudoku 129

He tried to fill in the next cell. Row 4, Column 5. Logic dictated it had to be a '6'. He wrote '6'.

Standard Sudoku rules still apply. If you know a "1" cannot go in a certain box due to existing numbers, you can immediately eliminate that column number from the possible candidates in Column 1 [34]. Remember that every row, column, and

: In these puzzles, the numbers in columns 1, 5, and 9 act as "addresses" for the digits 1, 5, and 9.

: The puzzle should be solvable through logic alone, without requiring guesswork. A good Sudoku puzzle will allow solvers to use deduction to figure out which numbers can go in each blank cell.