Extra special – Butterfly Killer Sudoku (hard)

Somehow butterfly puzzles have been neglected in the past few months and it’s time to rectify. A quick reminder – this breed of overlapping sudoku puzzles was suggested by udosuk and implemented by myself.

There are 4 “classic” 9×9 Killer Sudoku puzzles inside this one. They all overlap and they all must be solved according to the rules of Sudoku. You can (in fact, you must) use the Twin Nonets solving technique for this one!

Have fun!

7 Comments

  1. I’ve tried downloading this puzzle a few times but all I get is an ordinary killer. Love all your overlapping killers and clueless killers and can’t get enough of them!

  2. Hi Sandra,

    not sure why you are getting an ordinary killer. Look carefully – it’s a 12×12 puzzle, not 9×9.

    4 sub-puzzles overlap heavily so you may not have noticed that it’s a butterfly…

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