Programs which generate, solve, and analyze Sudoku puzzles

Postby xemnosyst » Sat Jan 30, 2021 1:29 am

A sudoku web app with a help menu to visualize many different strategies you could use on the current board. Play at

Other features:
- "Auto apply" any strategy to have the app apply as you play. Personally, I let the game erase candidates and apply naked singles for me.
- Play within your web browser; no need to install anything.
- Alternatively, "Add to homescreen" from Chrome or Safari. It will look and feel similar to a native app, and can be played offline.
- Share a link to your current game exactly as you have it. E.g. ... urqxlw1PNF
sudoku screenshot desktop.png
You can keep the help menu always visible on desktop
sudoku screenshot desktop.png (72.31 KiB) Viewed 250 times
sudoku screenshot phone.png
A clean UI that works well on a phone
sudoku screenshot phone.png (51.61 KiB) Viewed 250 times
Posts: 3
Joined: 24 January 2021


Postby creint » Fri Feb 05, 2021 4:11 pm
64: Continuous loop of 6
You are missing -1r7c6, seeing both on and off, don't know if that is still within the definition.

Could it be nicer if you render the digits on top of the drawing instead of behind?
Is there an import function?
Posts: 322
Joined: 20 January 2018


Postby xemnosyst » Fri Feb 05, 2021 5:46 pm

Thank you for checking it out, and for the feedback!

Interesting observation about that loop. It never occurred to me that you could eliminate candidates based on non-consecutive members in a loop. Makes sense! I will add that to my TODO list.

I do see what you mean about the lines obscuring the numbers. I spent some time on colors recently, and I think it's worse now. Changing the rendering order could be a bit more involved ... maybe I can make the lines a little translucent to mitigate the issue as a quick improvement, even if that wouldn't be as nice as rendering the lines under the numbers but still over the highlighting & grid.

There is an import function. From the menu button in the top left, go to "Share" then "Import from clipboard". If it recognizes what you have in your clipboard that will do the import, otherwise it will popup up a dialog explaining the format needed.
Posts: 3
Joined: 24 January 2021


Postby xemnosyst » Sun Jul 18, 2021 1:59 pm

A few more features to point out since February:

  • Enter a custom game, editing the givens
  • Set light/dark theme
  • Import & export puzzle strings
  • The help menu finds and visualizes nets
  • Viewing a net lists other strategies that would be equivalent in that case. This is a work in progress. So far it recognizes these equivalents:
    • Hidden single
    • Omission
    • Hidden pair
    • Naked pair
    • Complex x-wing, listing base and cover sets
    • Turbot fish
    • Empty rectangle
    • Unique rectangle types 1, 2, 4, 5, and 6
    • Hidden rectangle
    • Avoidable rectangle types 1, 2, 4, 5, and hidden
    • XY-wing
    • XYZ-wing
    • W-wing

For example check out the nets in the help menu for this game. (I wanted to attach a screenshot, but is errors with "the board attachment quota has been reached".)
Posts: 3
Joined: 24 January 2021

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