Solver App for Android
Sudoku Solver
for Android
Updated 14 June 2025
Read the update
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Sudoku+ Solver (Beta)
Solve Path now excludes unchecked strategies ↓
Candidates can be Edited or Highlighted Chained Coloured,  Shown
Enter clues or solutions
1 2 3 4 5 6 7 8 9
Auto Clear
Clues+Solved: 0/81

Step 1: Choose the 'constraint'
Step 2: Pick an example here


Key
Show bi-values cells
Show Strong (bi-location) links in
Windows
Boxes Rows Columns
1 2 3 4 5 6 7 8 9
Box numbers referred to in results:


Help on String Definitions used in this solver for transporting puzzles
Now updated and expanded!
Note: All Chaining strategies now permit cycling alternatives, where found read more



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Version 2.41.1

Coordinate system: Letter/Number rYcX

See the Strategy Home Page for strategy guides
1
2
3
4
5
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9
Check for Solved Cells   
Show Possibles  
 1: Singles  
 2: Naked Pairs/Triples  
 3: Hidden Pairs/Triples 
 4: Quads 
 5: Pointing Pairs  
 6: Box/Line Reduction  
Tough Strategies
 7: X-Wing  
 8: Simple Colouring  
 9: Y-Wing  
10: Rectangle Elimination  
11: Swordfish  
12: XYZ Wing  
Diabolical Strategies
13: X-Cycles  
14: XY-Chain  
15: 3D Medusa  
16: Jellyfish  
17: WXYZ Wing  
Extreme Strategies
19: Grouped X-Cycles  
20: Finned X-Wing  
21: Finned Swordfish  
22: Altern. Inference Chains 
23: Sue-de-Coq  
24: Digit Forcing Chains  
25: Nishio Forcing Chains 
26: Cell Forcing Chains  
27: Unit Forcing Chains  
28: Almost Locked Sets  
29: Death Blossom  
30: Pattern Overlay Method  
31: Quad Forcing Chains  
"Trial and Error"
32: Bowman's Bingo 


Errors? [CRTL]+[F5] to clear and download the latest script files

The Sudoku+ Solver

UNDER DEVELOPMENT

All feedback, comments, arguments, bug reports and strategy ideas are welcome. There is a new FEEDBACK form with a column displaying comments and questions. Many thanks to all the people who have done so and helped improve this solver.



Version 2.42 (September 14th 2025)
Added Windoku

Full version history here

Solver help

Use the "Import a Sudoku" button or type in a Sudoku puzzle in the small board.
You can also 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 use the [<<] button to step back one go. Toggling between Take Step and [<<] helps you see the changes.

Pressing "Enter" on the keyboard after clicking on Take Step is a quick way to activate "Take Step". Details of any solutions will be written out in the text box below the big board. Strategies are ordered by complexity. Any strategy that is successful returns the step-through to the start.

Click on the board to highlight sets of numbers. You can edit the Sudoku at any time - entering solutions in the small board or editing candidates. (Toggle between highlighting and editing using the radio buttons at the top.)

All Solutions to a Sudoku+
Logo
By Andrew Stuart and Rui Gonçalves, Syndicated Puzzles


Email your puzzle to a friend
Logo
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.


 
 

Custom Sudoku+ Puzzle

You can create a custom shape and it will be stored as a cookie.

Choose colours in the top row and click on cells on the board.

Your Sudoku+ is ready when all colours have nine cells

Start with an existing pattern:


and clear board of clues


   

To use more than one custom shape load them from the parameter line. Look at the format in [Email This Board] and substitute your 81 character custom map for the shape number.

Attempting to minimise the number of clues...
Logo Warning: Expect long processing if the minima is more than 10 clues away.
Maximum number of clues is 40. Minimum is 17.
Cancel if excessive.
Removed: Recursed Still Going! Finished!

Import a Sudoku+ Puzzle
X
Logo Clues String
Paste in the clues - 81 characters long


Shapes - represented by a colour map string
Paste in a 81 character string (1 to 9)


Packed String
Paste in a 246 character string containing packed data


To see an example use the Email button