For the most varied range of sudoku puzzles with the widest range of difficulty available anywhere look no further than the Observer"s " Killer Sudoku". Combining elements of sudoku & kakuro these headscratchers will test the skills of even the most practised sudoku fan. This collection contains 150 previously unpublished puzzles of varying levels of difficulty so whether youre new to the Killer Sudoku grid or are a seasoned solver looking for a challenge this book will keep you occupied. Be warned though
- some of these puzzles are so fiendishly difficult they may well keep you up all night."