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Feedback and Questions

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. Please feel free to drop me a note on the side of the page or try the Facebook comment box. Or you can email me directly at .

Post a Comment or Question here...
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Any Sudoku you want to publish here for easy loading into the solver - 81 characters, use '.' or '0' for unknowns.

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Many thanks to all the people who have helped improve the solvers and strategies with their feedback!

Wednesday 14-Apr-2021

... by: Andreas, Germany

Good to hear that you could restore (most of) your website. I am missing the Kendoku Solver. There is a daily Kendoku in my local newspaper, but I am not able to solve it every time. So I was happy to find your website.
Found no useful alternatives on WWW.

Andrew Stuart writes (18-Apr-2021):

Yes I had to take down the KenKen solvers since by program won't activate on the new server. I don't know why, the settings and permissions are identical to the Sudoku program. Really frustrating. Requires deeper knowledge of windows 10 than I have

Sunday 11-Apr-2021

... by: ATechGuy, United States


I was so saddened to hear your site had been hacked. As an IT MSP, we see it all the time and it's such negative energy. Your Apr 11 update made my day that you were able to recover your site. I so love your solver--it has taught me a lot about the puzzle. Sudoku is part of my life and I try to "wake up" my brain every morning by doing a few puzzles. I'm sure it also helped keep my mother's brain more active in her last years.

All the best,

Andrew Stuart writes (18-Apr-2021):

Thanks Ken!
Always appreciate a thumbs up from visitors

Saturday 10-Apr-2021

... by: Conway, England

You have a link for a pdf relating to creating and grading puzzles, unfortunately following the link says there�s not article found. Having spent 12 months of lockdown working on a sudoku engine I�m now at that stage where producing a puzzle is reasonably easy, but producing an interesting puzzle worth playing is a bit hit and miss. That PDF might be very helpful to me. No rush though, I think my sudoku bug is here to stay for a while. Interestingly I started my project with much the same view as you... there can�t be that much to this puzzle, haha, how wrong I was.

Andrew Stuart writes (11-Apr-2021):

Thanks for telling me, hard to know what's missing after the big restore. I have to do it very piecemeal since there are changes (mins and visitors) all the time. The document is now back on the site.

Friday 2-Apr-2021

... by: Douglas Boffey, England

There seems to be a broken link, namely to /Gurths_Theorem

I know this is rather an esoteric technique, and not easy to explain.

Andrew Stuart writes (11-Apr-2021):

Page now restored having got the pre-hack wiki back.

Thursday 1-Apr-2021

... by: Peter Foster, United Kingdom

Hi I have a Killer Sudoku from Puzzler #181 that the solver can't crack.

I'm not sure if it is because the strategy required hasn't been programmed or whether the puzzle is flawed.

If you are interested, is there a way I can send it to you ?

Many thanks


Andrew Stuart writes (11-Apr-2021):

Yes the Killer solver does lag behind the Sudoku in terms of solving power. Mainly because there are zillions more candidates and the chaining strategies can't bite
I have example that don’t complete, so no sweat

Saturday 20-Feb-2021

... by: Richard Pasma, United States

Thank you so much for all the work you have done and are doing in providing an excellent and probably the best resource there is for people interested in puzzles. Since the web site has been recovered I have not been able to get the Sudoku Solver -Solution Count button to work. It returns a on the address line and an "Article Not Found" as a result. It was working well for me before the crash. I am using Windows 10 and tried getting it to work with IE, Fire Fox and Chrome to no avail. Thanks again, Rich

Andrew Stuart writes (20-Feb-2021):

Restored it this morning. Quite difficult to remember how to install a DLL in the web server environment, but dredged it out of memory somehow

Friday 19-Feb-2021

... by: Tom, Connecticut USA

So sorry about the vicious hack. I'm saddened that our world has people so evil as to destroy Andrew's site that has given pleasure to so many people the world over. When I was working I used to purchase monthly puzzle packs both as a way to support the site, and give me diversions on long flights. I especially enjoy the symmetrical patterns of the daily puzzles. I'm going back to purchasing monthly puzzle packs as a way to support the site financially.

Andrew Stuart writes (20-Feb-2021):

Thanks you very much! Really appreciated and very heartening to hear
My pleasure

Tuesday 16-Feb-2021

... by: Dikla, Israel

Why the daily jigsaw does not display on the web page?
I have enabled Javascript.

Andrew Stuart writes (16-Feb-2021):

Jigsaw player is back online. Still have to work out why the state is not saving in cookies

Sunday 14-Feb-2021

... by: Mark Boyd, Canada

Welcome back. You were very much missed.

Andrew Stuart writes (14-Feb-2021):

Thank you !

Sunday 14-Feb-2021

... by: Philip Trueman, England

Has the definition of 'midnight' changed as a result of the hack/restore? Not complaining at all, just asking.

Andrew Stuart writes (14-Feb-2021):

It has. The old server was set to US Eastern Standard Time and is now on GMT
This was just how it came and it was too late to change it
It's in my job queue to go through the player feed scripts and add some kind of adjustment
EST was fair to the US and Europe

Saturday 13-Feb-2021

... by: Eugene, US

I made a small donation...hopefully it helps a little with the recent hack. Hope it gets sorted out!

Andrew Stuart writes (14-Feb-2021):

Thank you! Going towards a better backup system, for sure.
Really appreciated
All the best
Andrew Stuart
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