Here's another Sudoku. HoDoKu rating Extreme(5604) : r/sudoku
HoDoKu 2.1 Download (Free) - hodoku.exe
HoDoKu: User Manual (Chapter 2: Playing the Game)
Hodoku Grouped AIC II | Systematic Sudoku
Brutal puzzle I found on hodoku, took me around 2 and a half hours. If anyone is feeling brave enough to give it a shot let me know how you do. :
Can Hodoku have more than 1 solution? When I tried to use Swordfish on candidate 3 in column 5 and 6, it tells me error to exclude 3 in r1c7. : r/ sudoku