Advanced Solving Strategies
When basic techniques are not enough, these advanced strategies will help you solve even the most difficult puzzles.
X-Wing Pattern
The X-Wing eliminates candidates when the same candidate appears in exactly two cells in two rows, aligned in the same two columns.
Swordfish Pattern
Swordfish extends X-Wing to three rows and three columns. It follows the same logical principle but is more complex.
XY-Wing
The XY-Wing involves three cells forming a wing pattern. The pivot cell shares a unit with two wing cells.
Practice Tips
Start with simpler patterns before attempting complex ones. Use pencil marks and practice pattern recognition.