Techniques · sudoku
Unique Rectangles
Four cells in two rows, two columns and two boxes cannot all share the same pair, or the puzzle would have two solutions. That rules out a candidate.
In the walkthroughs, every Unique Rectangles step shades the cells of the pattern and names the cell and digit it proves, so you can see the move on the grid rather than read about it. Press “Skip to next hard step” to jump straight to it.
Worked examples
Puzzles from the books where Unique Rectangles is used. Each link opens the full step-by-step solution.
Extreme Sudoku 1 (5 of 150 puzzles)
- Puzzle 51 · Expert 7
- Puzzle 94 · Expert 7
- Puzzle 97 · Expert 7
- Puzzle 131 · Expert 7
- Puzzle 132 · Expert 7
Extreme Sudoku 2 (7 of 150 puzzles)
- Puzzle 37 · Expert 7
- Puzzle 83 · Expert 7
- Puzzle 86 · Expert 7
- Puzzle 89 · Expert 7
- Puzzle 120 · Expert 7
- Puzzle 121 · Expert 7
- Puzzle 150 · Expert 7
Where it sits
See the whole ladder on hard sudoku techniques, or look a puzzle up by number under solutions.
