Using the ‘Swordfish’ Sudoku solving technque
After you have tried all the easier strategies and find no new squares to solve (single possibility, only square, excluded hidden twins, naked twins, excluded subgroup), it may be worth looking out for Swordfishes.
Other guides available
For generation and solution of Sudoku puzzles download and install Sudoku Dragon.
It is the complete Sudoku package, including hints, guides, and many new puzzle types. Download our Sudoku puzzle solver for a free 23 day trial.
Copyright © 2005-2015 Sudoku Dragon