I've received a lot of interesting comments and questions from Sudoku fans over the last few years and this page
is where I try to answer them. I'm also directing Str8ts feedback here. Please feel free to drop me a note on the side of the page. Or you can email me directly at andrew@str8ts.com.
Post a Comment or Question here...
Friday 5-Dec-2025
... by: 39_Chevy, USA
The Solver is still not working for the Jigsaw. When loaded into the Solver the numbers appear to be OK, but the grid changes.
For the past 2 nights, Dec. 4 & 5, 2025, the Jigsaw solver shows the given clues in the correct positions row & column, but the pattern in the Solver is different from the pattern in the Puzzle. If I solve a cell & check with the Solver, same problem, wrong pattern from the Puzzle yielding 0 Solution Count
Andrew Stuart writes:
True, thanks for detecting. Was a very recent change. Try now
Tuesday 2-Dec-2025
... by: Matt, DC, USA
This summer, a change was made to refuse to process any sudokus with less than 17 givens. This has made your tool significantly less helpful for variant sudokus, such as Thermos, Killers where some regions have no sums, or Just One sudokus where only one digit can be deduced with confidence.
Would you consider changing the 17 clue requirement from an error to a warning, and still let the existing logic do what it can?
Andrew Stuart writes:
I thinking about this. Need to do some testing. Quite possible
Tuesday 2-Dec-2025
... by: Leo, Germany
Playing on str8ts.com with my Android phone the browser annoyingly tries to select the text on the number-buttons when i use them. Could be an easy fix, to disable text selection for the buttons via CSS: .numberpad { (...) -webkit-user-select: none; user-select: none; }
Thank you for providing lots of free puzzles! Greetings Leo
Andrew Stuart writes:
Thanks for the tip Leo, I've applied the css. Check now
Sunday 30-Nov-2025
... by: Clive Snashall, UK
The new Killer entry system with the number selection is excellent!
Andrew Stuart writes:
Fantastic! Took a few goes but I think it's much slicker now
Thursday 20-Nov-2025
... by: Phillip, Little Rock, Arkansas
What a great site. I came just looking for new patterns for solving beyond what I had done for years, and I ended with a perennially open tab in my browser!
I'm truly impressed by the complexity of some of these solving methods, yet you have code to pull them off as well! I was in a long hiatus from Sudoku for many years, and then one day prompted an AI chat with a NYT sudoku I was stuck on... It UTTERLY failed to comprehend Sudoku at all. Tried, but failed. Then I fell in the rabbit hole: Can I write some front end to solve and create puzzles? How do you break down the steps we take in our heads and while solving? ...and so on. Not sure I came out on top of it all, but i did get somewhere: http://dice.phillipwildhirt.com/sudoku
Anyways, found your site and now the world has opened up! Just makes me want to start all over and try again! Thanks for your work!
Andrew Stuart writes:
Very kind words, thanks so much. Mostly I get bug reports (which I’m equally eager to get) but complements don’t have me hunting around code. Quite a slick UI you built there, well done. Enjoy!
Thursday 20-Nov-2025
... by: Jon, England
Hi / I’m not sure if it’s me, but I have noticed the following issue since using the new Version 2.47.1 of the suduko solver on my iPad :-
If you select a cell in the solver to edit the candidates (ie touch the cell on the iPad screen) and then realise it’s not the cell you wanted , you used to be able to immediately select another cell. With the new software if you select a second cell without hitting the return key first, it blanks (hides) the contents of the second cell selected.
You can make the cell candidates visible again by toggling the candidates shown tick box off and on, but it wont allow you to edit the candidates.
The only option I can find is to delete the ipad page and reload the solver from the daily page, thus losing all my edits in the solver.
I’ve tried removing the solver from memory and rebooting but to no avail.
Tested on 2 separate iPads.
Regards
Jon
Andrew Stuart writes:
My bad. I thought I’d tested it on iPads but I didn’t notice what it was doing when you clicked the second cell. Not too hard to fix, I’ve put an update out. If you refresh the solver page should be good Let me know
Wednesday 19-Nov-2025
... by: Peter, New Zealand
The Killer Sudoku Solver "New Killer" popup no longer seems to work in the Pale Moon browser :(
Andrew Stuart writes:
I did not know there was a Safari-based browser still being maintained. Downloaded and testing with it. Fixed the Killer entry issue and a bunch of font issues.
Sunday 16-Nov-2025
... by: Kate, Manchester, UK
I find this so handy when I've got really stumped on a killer. Thank you so much for doing this - clearly a labour of love (whether that's of numbers or coding ...)
However, I am struggling to get it to solve puzzle no 157 from dailysudoku.com https://www.dailykillersudoku.com/search?n=157 Their solution has 2 & 8 in H1 & J1 but Killer Sudoku Solver deduces that it should be 3 & 7 - and then it comes up with an error in G6 as it wants to put a 3 in this cell (when it should be a 2) Load Puzzle Keep up the good work
Andrew Stuart writes:
Good news, it does solve as of this evening
I’ve been struggling find a bug that is giving false positives on innies/outies giving a bad path down the line as you have discovered. It only seems to happen after the solver service has been running a few days, very odd. Anyway as of the update tonight you should be fine. I’ve put the link above if you need to load it again. Use “Email this board” to send me puzzles, especially if the muck up like that, very valuable report
Sunday 16-Nov-2025
... by: Henon, Austria
Could I please trouble you fixing a bug that causes one to make mistakes when eliminating numbers with highlighting in the solver? When you got a set of numbers highlighted and edit numbers it may happen that some cells get updated but the highlighting is not recalculated for those cells. That may result in overlooking numbers and making mistakes. As it is now, after making edits you have to un-highlight the numbers and highlight them again. All you need to do is remember the set of highlighted numbers and recalculate the highlighting for all cells. Thanks!
Friday 5-Dec-2025
... by: 39_Chevy, USA
Friday 5-Dec-2025
... by: John, Texas
For the past 2 nights, Dec. 4 & 5, 2025, the Jigsaw solver shows the given clues in the correct positions row & column, but the pattern in the Solver is different from the pattern in the Puzzle. If I solve a cell & check with the Solver, same problem, wrong pattern from the Puzzle yielding 0 Solution Count
Tuesday 2-Dec-2025
... by: Matt, DC, USA
Would you consider changing the 17 clue requirement from an error to a warning, and still let the existing logic do what it can?
Tuesday 2-Dec-2025
... by: Leo, Germany
Could be an easy fix, to disable text selection for the buttons via CSS:
.numberpad {
(...)
-webkit-user-select: none;
user-select: none;
}
Thank you for providing lots of free puzzles!
Greetings
Leo
Sunday 30-Nov-2025
... by: Clive Snashall, UK
Thursday 20-Nov-2025
... by: Phillip, Little Rock, Arkansas
I'm truly impressed by the complexity of some of these solving methods, yet you have code to pull them off as well! I was in a long hiatus from Sudoku for many years, and then one day prompted an AI chat with a NYT sudoku I was stuck on... It UTTERLY failed to comprehend Sudoku at all. Tried, but failed. Then I fell in the rabbit hole: Can I write some front end to solve and create puzzles? How do you break down the steps we take in our heads and while solving? ...and so on. Not sure I came out on top of it all, but i did get somewhere: http://dice.phillipwildhirt.com/sudoku
Anyways, found your site and now the world has opened up! Just makes me want to start all over and try again! Thanks for your work!
Thursday 20-Nov-2025
... by: Jon, England
If you select a cell in the solver to edit the candidates (ie touch the cell on the iPad screen) and then realise it’s not the cell you wanted , you used to be able to immediately select another cell. With the new software if you select a second cell without hitting the return key first, it blanks (hides) the contents of the second cell selected.
You can make the cell candidates visible again by toggling the candidates shown tick box off and on, but it wont allow you to edit the candidates.
The only option I can find is to delete the ipad page and reload the solver from the daily page, thus losing all my edits in the solver.
I’ve tried removing the solver from memory and rebooting but to no avail.
Tested on 2 separate iPads.
Regards
Jon
Let me know
Wednesday 19-Nov-2025
... by: Peter, New Zealand
Sunday 16-Nov-2025
... by: Kate, Manchester, UK
However, I am struggling to get it to solve puzzle no 157 from dailysudoku.com
https://www.dailykillersudoku.com/search?n=157
Their solution has 2 & 8 in H1 & J1 but Killer Sudoku Solver deduces that it should be 3 & 7 - and then it comes up with an error in G6 as it wants to put a 3 in this cell (when it should be a 2)
Load Puzzle
Keep up the good work
I’ve been struggling find a bug that is giving false positives on innies/outies giving a bad path down the line as you have discovered. It only seems to happen after the solver service has been running a few days, very odd. Anyway as of the update tonight you should be fine. I’ve put the link above if you need to load it again. Use “Email this board” to send me puzzles, especially if the muck up like that, very valuable report
Sunday 16-Nov-2025
... by: Henon, Austria
When you got a set of numbers highlighted and edit numbers it may happen that some cells get updated but the highlighting is not recalculated for those cells. That may result in overlooking numbers and making mistakes. As it is now, after making edits you have to un-highlight the numbers and highlight them again. All you need to do is remember the set of highlighted numbers and recalculate the highlighting for all cells. Thanks!