Strategies for Popular Number Puzzles

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Killer Sudoku Solver Please report any bugs. Tested in IE and Firefox.
Feedback: Form and User Comments/Questions Here
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

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 2.10
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: Swordfish  
19: XYZ Wing  
Diabolical Strategies
20: X-Cycles  
21: XY-Chain  
22: 3D Medusa  
23: Jellyfish  
24: WXYZ Wing  
25: Aligned Pair Exclusion  
Extreme Strategies
26: Grouped X-Cycles  
27: Finned X-Wing  
28: Finned Swordfish  
29: Altern. Inference Chains 
30: Sue-de-Coq  
31: Digit Forcing Chains  
32: Nishio Forcing Chains 
33: Cell Forcing Chains  
34: Unit Forcing Chains  
35: Almost Locked Sets  
36: Death Blossom  
37: Pattern Overlay Method  
38: Quad Forcing Chains  
"Trial and Error" 
39: Bowman Bingo

Welcome to this new Killer Solver

I have been solving and making Killer Sudoku puzzles since 2005 and although my Sudoku solver has been part of this site since those early days I have not attempted a public solver until now. The main reason I have shied away from attempting it was the complexity of the puzzle in terms of the user interface. However, I hope I have now come up with a satisfactory solution. 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 2.10 (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 1.99 (April 9th 2014)
Unchecked strategies are now saved in a cookie.

New in version 1.94 (May 25th 2013)
Fixed some bugs and improved the text returned from cage combinations. Made sure the 'last remaining cell' in a cage was correctly being identified and now shows on the Hidden Singles stage.

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

Solver created on 30-May-2009.
This page was last modified on 11-Jan-2023
All code and design is copyright and for personal use only and may not be reproduced elsewhere.
Copyright Andrew Stuart @ Syndicated Puzzles, 2005-2023