Properly Killer Sudoku

If you care about Killer Sudoku, this book is for you. We love puzzles as much as you do, which is why we’ve re-engineered our Killer Sudoku grids from the ground up to give you the best possible solving experience.

• Clearly shaded cages mean you can spend your time figuring out the solution, not wasting it trying to see the boundaries.
• Precisely sized clue numbers are perfectly legible yet don’t get in your way when writing in candidates.
• Every puzzle has been properly graded by our human-calibrated scoring system, giving you a smooth and satisfying progression from the easiest Easy to the hardest Extreme grid.
• Each puzzle has a single, verified unique solution. There is no guessing required: you can solve every puzzle with logic alone.
• With only two puzzles per 8.5” x 11” page (216 x 297mm), you won’t have to struggle to squeeze in notes and numbers.
• Puzzle numbers, scores and difficulty ratings have all been minimised to give you plenty of space for those all-important calculations and notes.
• A solving guide and cheat sheet complete the experience.
• With 300 puzzles ranging from easy starter grids to extreme challenges, you’ll find hours of enthralling entertainment inside.

Properly Clear

We've re-worked the Killer Sudoku grid from the ground up. Cages are subtly shaded and bordered, which makes it easier than ever to see boundaries at a glance.

We shrank the clue numbers, finding the optimum proportion between legibility and obstruction. They’re easy to read, but they won’t get in your way when you want to write in candidate numbers.

Optimised grids are great, but they mean nothing if they get squeezed down to tiny proportions to max out the number of puzzles. That’s why you’ll find just two grids on each large page. Yet they’re not so big as to be distracting; it’s important to be able to see the whole picture.

And because Killer Sudoku is as much about the calculations you do off the grid as it is the numbers you write on it, we’ve given you plenty of space for jotting notes and sums. No superfluous decoration, just the information you need, where you need it.

Properly Graded

You probably know the feeling: you’re in the mood for a moderate puzzle, something to kick your brain into gear but not too taxing. You get started, yet within a few moves you find yourself stuck, hit by an unexpected roadblock. Advanced techniques are required, but you’re in the “Easy” section.

Or, and this is even worse, you’re ready for a real challenge, something that will push your skills to the limit. You turn to the hardest puzzles in the book, settle in for a good long solving session, only to be disappointed by a maddeningly middling puzzle, solved in mere minutes.

Poorly graded puzzles are a common symptom of mass-produced publications. You shouldn’t have to put up with them. That’s why every puzzle in Properly Killer Sudoku has a difficulty score assigned by our human-calibrated scoring system.

We’ve analysed the techniques required to reach every solution. We’ve looked at the number of moves necessary, even taken into account how quickly you can place your first digits on each grid. And then we’ve come up with a difficulty score. For every single grid.

Real human players have calibrated the scores, completing grids and verifying difficulty levels. So “Easy” really does mean easy, and “Extreme” puzzles really are harder. No more nasty surprises.

Properly Killer

You’ll find everything you need for the best puzzle-solving experience. There’s a solving guide, so even if you’ve never played before, you’ll be ready to hit the ground running.

You’ll also find our popular “Cheat Sheet” inside. And of course, the full, unique solution to every puzzle is included at the back, making it super fast to check your results.