Strategies for Popular Number Puzzles
Weekly 'Unsolvable'
Puzzles to Play
Killer Sudoku Solver
Please report any bugs and feedback welcome
Click to edit candidates or enter a solution: Show Candidates

1 2 3 4 5 6 7 8 9
Auto Clear
Clues+Solved: 0/81
Help on Killer Definitions used here for transporting puzzles
Quick help: Using this Solver

You can pick examples from the list above. Click on Take Step to step through the solution. Unknown squares are filled with 'candidates' - possible solutions.
Any cells that are reduced to one possible candidate are solved.

You can enter a new Killer puzzle using the new 'designer' - click on "Enter new Killer". Once you fill in the clues and set up the cages correctly it can be solved.

Unlike the other solvers you can only edit the main board when solving. The small board only displays the clues.
Version 2.19
See Strategy Overview documentation

Coordinate system: Letter/Number rYcX

Check for Solved Squares   
Show Possibles  
1: Hidden Singles  
3: Naked Pairs/Triples  
4: Hidden Pairs/Triples 
5: Quads 
6: Killer Combinations (easy)  
7: Innies and Outies (1 cell)  
8: Pointing Pairs  
9: Box/Line Reduction  
Tough Strategies
10: Cage Splitting  
11: X-Wing  
12: Simple Colouring  
13: Y-Wing  
14: Innies/Outies (2+ cells)  
15: Killer Combo's (hard)  
16: Cage/Unit Overlap  
17: Cage Compare  
18: Rectangle Elimination  
19: Swordfish  
20: XYZ Wing  
Diabolical Strategies
21: X-Cycles  
22: XY-Chain  
23: 3D Medusa  
24: Jellyfish  
25: WXYZ Wing  
26: Aligned Pair Exclusion  
Extreme Strategies
27: Grouped X-Cycles  
28: Finned X-Wing  
29: Finned Swordfish  
30: Altern. Inference Chains 
31: Sue-de-Coq  
32: Digit Forcing Chains  
33: Nishio Forcing Chains 
34: Cell Forcing Chains  
35: Unit Forcing Chains  
36: Almost Locked Sets  
37: Death Blossom  
38: Pattern Overlay Method  
39: Quad Forcing Chains  
"Trial and Error" 
40: Bowman Bingo

Welcome to this new Killer Solver

Killer Sudoku solver has quite a complicated definition and I hope the method I've created to enter a puzzle works for most people. The independent 'Designer' handles the entering of the clues and cages. Keeping this separate and being able to (loosely) validate the entry should allow puzzle solvers a fairly quick way of setting up the puzzle for solving. I hope you agree and I'd love to hear your feedback.

You should also be aware of the Killer Cage Convention.

New in version 2.13 - 2.16 (May 2024)
Added the ability to transport a Killer puzzle in progress with all the solved cells and candidates. Available in the [Email this Board] button.

New in version 2.16 (October 23th 2023)
Important update thanks to JohnNoneDoe who supplied an example, I have improved the Innies and Outies strategy. Particularly outies which he observed, do not need to obey the Dog-leg restriction on the pseudo-cell they create. This improvement has a large effect on hard Killers improving the hit rate (I hope). I have also changed how a block displays so as not to override the cell colours.

New in version 2.09 (October 25th 2022)
Made cells with incorrect numbers look better and moved popup alert to results box; new catch for cages not adding up to the clue.

New in version 2.06 (September 8th 2017)
For Naked Pairs in a cage I've added the case where the two cells are diagonally positioned.

New in version 2.03 (August 29th 2015)
Killer Cage Convention will now clear off candidates in 'dog-leg' cages early in the list of checks - as and when solution numbers are found.

New in version 1.91 (October 16th 2012)
Re-wrote the Innies/Outies algorithm to look for innies with more than one cell covering several sticking-out cages. Re-ordered the strategies to balance them against new calibrations.
Added Cage Comparison to the killer strategies.

New: Version 1.02 (June 13th 2009)
Killer Sudoku Solver released

Email your puzzle to a friend
Copy and paste the contents of the green box into your email program and send it off.
The links contain the puzzle which will load when your friend visits the Sudoku Solver.
Solver created on 30-May-2009.
This page was last modified on 27-May-2024
All code and design is copyright and for personal use only and may not be reproduced elsewhere.
Copyright Andrew Stuart @ Syndicated Puzzles, 2005-2023, Privacy

How to enter a
Killer Sudoku

1) Click on the black line between the squares. This will connect cells to make the 'cages'.

2) Enter the numbers into the top left most cell for each cage.

3) Validate. To check you have entered a correct puzzle press validate. 'Cancel' will not save your design.

All cages must add up to 405. Current total: