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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 .

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

Tuesday 8-Aug-2006

... by: Paul McIlfatrick, Northern Ireland


I reALY like the changes you have made with v1.32 allowing various strategies to be selected/unslected when solving a Sudoku.

Suggestion for a minor enhancement:

As the first thing I do is to untick all of the Tough Strategies, Diabolical Strategies, Evil Strategies, and Trial and Error boxes, I would really appreaciate a tick box for each of these strategies that would toggle between switching them off/on.

Thanks and keep up the great work!

Paul McIlfatrick

Andrew Stuart writes (9-Aug-2006):

That's a good suggestion. I also want to add a checkbox to remove all strategies that assume uniqueness - Unique Reactangles, Empty Rectangles and BUG.

Thursday 3-Aug-2006

... by: bill o, new york city

can i buy a version of the solver that will run on my laptop when i'm not connected to the internet?

i'm a stone cold rookie at the game and your step by step display with explanations has been an invaluable tutor.



Andrew Stuart writes (4-Aug-2006):

I'm working on an updated version of the Sudokulist which will have all this and more for off-line use. First I've got to update all the documentation which is still lagging behind the strategies.

Wednesday 2-Aug-2006

... by: Ben, USA

I forgot to mention...fantastic site. It looks like you've logged many hours into this site...well done.

Andrew Stuart writes (4-Aug-2006):

Thanks Ben

Wednesday 2-Aug-2006

... by: Ben, USA

Load Sudoku:

Another question, just after the last move I didn't understand, the unique rectangles, the "XY-Chain" popped up. I click on the link but their is no desription as to how the XY-Chain works. I get the reason "XY CHAIN length=5, 5 taken off R3C7, chain ends: R3C2 and R8C7." I looks like a chain of 7s, but then the last square has no 7???


Andrew Stuart writes (4-Aug-2006):

OK, documentation updated to include XY-Chains.

Wednesday 2-Aug-2006

... by: Ben, USA

Load Sudoku:

I have a question...I'm trying to figure out the advanced techniques...and I've read the section on unique triangles but cannot understand the explanation given from the program. If you run the solver to the first time it uses unique rectangles, it reasons "HIDDEN UNIQUE RECTANGLE removing 5 at R9C9 because of R89C19 and two strong links on 2", and "HIDDEN UNIQUE RECTANGLE removing 1 at R7C4 because of R97C84 and two strong links on 9." I have two questions...the puzzle only has one square where there are only 2 candidates. In the examples there is always 2 squares with 2 candidates (or more). So in trying to figure out...I can't for the life of me figure what "and two strong links on X" means. Please help.

Thanks very much

Andrew Stuart writes (4-Aug-2006):

Ah yes, the Hidden Unique Rectangle. I don't know if anyone on the forums has officially - as offically as it can be - said this is Type X or whatever, so I've avoided a Type number and called it this. I'll be adding it to the docs soon.

Wednesday 2-Aug-2006

... by: Coke, UK

Hi, I,m using firefox and have found that since the last update the printable version occupies a much smaller section of the printable page (A4). Is this correct as when the possibles are more than 3 it makes the solving more difficult what with the deletions
Thanks and regards
Al Cockayne

Andrew Stuart writes (4-Aug-2006):

I'll check but I didn't change the format for printable versions.

Tuesday 1-Aug-2006

... by: Hansel, India

Yours is an excellent site I have ever seen for solving sudokus. I always refer here in case of doubts. It's a great amazing piece of work I should say !!!!! Great going !!!!!!

Andrew Stuart writes (4-Aug-2006):

Wow, thanks!

Sunday 30-Jul-2006

... by: sabina mongia, hong kong

when i open the page the page doesnt open fully. there is only half a grid there?
is there a problem. i love the solver and it has helped me a lot to understand the various eliminations. it is disheartening to see that i am not able to use it now.

Andrew Stuart writes (31-Jul-2006):

Nothing has changed this end and it works fine for me. Have you recently changed your browser security settings? Did you disable javascript? Does it work properly today?

Thursday 27-Jul-2006

... by: Irish Pete, NI, UK

Do you have any plans to add the "Solution Count" option to the PC version of the solver?

Andrew Stuart writes (31-Jul-2006):

Yes. The next version will be a complete re-vamp with everything on the on-line solver plus more. Any previous customers will be entitled to free upgrades.

Tuesday 25-Jul-2006

... by: Dina, Florida USA

Does this helper work with Safari for Mac? I was using IE and I switched. It seems to work fine in Safari unless I click on the "tests" for more information. When I return to my puzzle it's gone and I get the starting puzzle again, even after I've saved my puzzle I was working on.

Andrew Stuart writes (25-Jul-2006):

Should do - compatible javascript. I think what is happening is that a new window is not popping up. If you navigate away from the page you'll loose everything. It *should* open a new window from that point. Save can't save anything to your machine unless I use an intrusive cookie and that sparks more security popups than its worth.

Sunday 23-Jul-2006

... by: Terry Stewart, Rochester, Minnesota, USA

Load Sudoku:

I reentered the puzzle and ran it again with the current version and got a different result. I guess it is possible that I did not enter the puzzle correctly the first time, but I don't think that is true.
Terry Stewart

Andrew Stuart writes (23-Jul-2006):

See below
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