Killer Sudoku combines classic Sudoku with an extra constraint: groups of cells called 'cages' are outlined with dashed borders and labeled with a target sum. You must fill every row, column, and 3x3 box with 1-9 (no repeats), AND the digits inside each cage must add up to the cage's target number with no repeated digits within that cage.
How is Killer Sudoku different from regular Sudoku?
In regular Sudoku you get pre-filled numbers as clues. In Killer Sudoku the clues come from colored cages instead: each cage shows a sum that its cells must total. Digits cannot repeat within a cage, just like they cannot repeat in a row, column, or box. This means you use arithmetic as well as logic to solve the puzzle.
What are the best strategies for solving Killer Sudoku?
Start with the 45-rule: each row, column, and 3x3 box sums to 45, so if a cage is entirely within one of these, you can deduce missing values. Look for cages where only one combination of digits is possible (e.g. two cells summing to 3 must be 1+2). Use pencil marks to track candidates and eliminate digits that would violate the no-repeat rule in cages, rows, columns, or boxes.
What difficulty levels are available?
PlayBrain offers three difficulty levels: Easy (more given digits and smaller cages), Medium (fewer givens and mixed cage sizes), and Hard (very few givens with larger cages). All puzzles are algorithmically generated with a unique solution guaranteed.
Can I play Killer Sudoku on my phone?
Yes! This Killer Sudoku game is fully responsive and works on smartphones and tablets. Tap a cell to select it and use the on-screen number pad. The game supports pencil marks, undo, error highlighting, and a timer on all devices. No app download needed.
Killer Sudoku merges classic Sudoku logic with Kakuro-style cage sums for a uniquely demanding puzzle experience. The grid follows standard Sudoku rules where each row, column, and 3x3 box must contain the digits 1 through 9 without repetition. Additionally, dotted cages group certain cells together, and the digits within each cage must add up to the specified sum with no repeats. This dual constraint system means you must simultaneously track Sudoku placement rules and arithmetic totals. Killer Sudoku typically provides fewer given digits than standard Sudoku, relying instead on cage sums to guide your deductions. It is the perfect challenge for Sudoku veterans seeking a tougher and more mathematical variant.
How to Play
Note the dotted cages and their target sums, which tell you what the cells inside must add up to
Fill each cell with digits 1 through 9 following standard Sudoku row, column, and box rules
Ensure digits within each cage sum to the target number with no repeated digits in any cage
Cross-reference Sudoku constraints and cage sums to narrow down possibilities and solve the grid