Welcome to Killer Sudoku!

Killer Sudoku is a fun variant of the popular traditional Sudoku puzzle! This logic puzzle combines the classic structure of Sudoku with a bit of number-crunching.  Like standard Sudoku, the objective of each Killer Sudoku puzzle is to fill in the grid with digits 1 through N (where N is the number of rows or columns in the grid) in such a way that no column, row, or grid block contains the same number twice. Also known as Sum Sudoku, Killer Sudoku distinguishes itself with sub-regions or ”cages’ where the numbers within each cage must add up to the sum displayed and no numbers may repeat within a cage. This game tests both your number-placing skills and your ability to reason logically, offering a rich problem-solving journey for those seeking a mental workout beyond ordinary Sudoku.

The Basics

The Grid: Killer Sudoku is played on a square grid, usually 9×9, but it can vary in size. Each grid also has smaller grid blocks that are 3×3 on a 9×9 grid.

The Cage: The cage is groups of cells typically indicated with a dashed line. No numbers may repeat within a cage.

Sum Clues: In each cage is a numerical value. This is the sum the numbers within the cage must add up to.

Killer Sudoku Rules

In a Killer Sudoku puzzle, you will be presented with an NxN grid.  You must fill out the grid using the numbers 1 to N and the following rules must be adhered to:

• Use all digits 1 to N in each row, column, or grid block.
• No digit may repeat within a row, column, grid block, or cage.
• The digits within a cage must add up to the total indicated for that cage
• The puzzle is solved when all cells in the grid are filled in without violating any rules

Useful tips

• Pencil and eraser are your friend!
  Make sure you use a sharp pencil with an eraser. When you first start solving Killer Sudoku puzzles, you are likely to make mistakes. Even seasoned Killer Sudoku puzzlers make mistakes.
• Pace yourself
  Accuracy is more important than speed. The more accurate you are as you solve the puzzle, the less likely you are to makes mistakes. If you make a mistake, sometimes you can recover easily. However, if the mistake is one you don’t catch until the puzzle is almost complete, you may need to backtrack all the way to the beginning. And don’t worry, as you solve more Killer Sudoku puzzles, you will get better at applying your logic and your speed will organically increase.
• Approach each puzzle systematically
  Start with the obvious and move to the more difficult parts of the puzzle. For instance, begin with sum cages with the fewest cells and that have few options for the given sum total.
• Practice, practice and practice!
  Killer Sudoku is about applying math, logic, and problem solving skills. These are skills we all have on some level, but new skills take time to develop. The more you practice and play Killer Sudoku puzzles, the better you will get at accessing the logic you’ve learned and applying that logic to solving them regardless how difficult.
• Use a notation system
  As you begin to solve Killer Sudoku puzzles, find a useful notation system that works for you. Then as you play, use this notation system to keep track of all the decisions you make as you apply your logic and math skills. A good notation system to start with is the one that is commonly used for traditional Sudoku.

Killer Sudoku Solving Strategies

• Find cages with 1 cell
  If you find a cage with 1 cell, fill it in with the cage value.
• Find extremes
  Look for cage values that are very high or very low. These will have the fewest number of combinations to equal that value.
• Sum Elimination
  Depending on the number of cells in a cage and the sum value, there may be only a limited set of combinations. For instance, if you have a 2-cell cage and the sum value is 3, there is only 1 possible combination – 1+2=3. If a 3-cell cage and the value is 6, the only possibility is 1+2+3=6
• Remember the Rule of 45
  The Rule of 45 is a rule that applies to all rows, columns, and sub-grids. Each can only add up to 45 (1+2+3+4+5+6+7+8+9 = 45). Use this to help you figure out cage numbers.

 

Remember

Every Killer Sudoku puzzle has a solution. Be patient, work methodically, and take notes on the strategies you use as you progress through the puzzle.

Happy Puzzling!

 

Are you looking for Killer Sudoku puzzles? Then look no further than the Puzzle Shop!

In the Puzzle shop, we have Killer Sudoku puzzles from easy to hard. You can also find other Sudoku variants to challenge your logic skills.