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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. 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...

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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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Comment, question or feedback:

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letters you see:

If you are writing to alert me of a problem (thank-you!) please include a url to the page in question.
Can get fixes in quicker if I know immediately where to go.

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

Thursday 1-Aug-2024

... by: Paul, Germany

Load Sudoku: CLICK TO LOAD

Greetings!

[This] has, at step 1, four naked pairs. However, in the Solve Path you list seven naked pairs: one is listed in column 7(A,B) and also in box 3; another is listed in column 1(E,F) and also in box 4; and so on. In other words, three out of the four naked pairs are shown in the Solve Path twice: once in a column and once in a box. I hesitate to say that this is wrong, but could perhaps the Solve Path listing be optimised so that it eliminates double entries?

TIA, Paul

Andrew Stuart writes:

That’s a fascinating example and quite insane. Pairs usually don’t stack up quite like this and it usually isn’t a problem. I feel I have to show all examples in one round otherwise the take step could get tedious. In this case I can see that finer steps would be better. The thing is I save all the eliminations until the strategy is finished to avoid knock-on effects. I feel I might introduce bugs if I make a complicated filter for this edge case

Wednesday 31-Jul-2024

... by: rocky, earth

I tried the 6x6 KenDoku® Solver. When I edit the candidates, they disappear and cannot enter again. Can you pls check this? Thanks

Andrew Stuart writes:

Fixed! Undeclared variable. Oops. Refresh the page

Monday 29-Jul-2024

... by: Lincoln Kinnicutt, Boston

For the past several days, the jigsaw solver does not work. Cannot load an Archived or imported Sudoku into it.

Thanks.

Andrew Stuart writes:

Ok fixed this now! Tough one but got there

Saturday 27-Jul-2024

... by: Carl in 't Veld, The Netherlands

I use your fantastic site a lot to continuously learn new sudoku tricks. I wonder if you are planning a mobile friendly version?

Andrew Stuart writes:

I’ve tried! I really tried to make the site work on Mobile. The puzzle players seem to be decent enough. Okay I’ve not tried to make the solver work on mobile – it is just too big. I was hoping people would use the Android App but sales are slight. I will attempt a small solver version for mobile in the near future. But have to consider if it will pay for the costs. Is something I’d like to do. Maybe a supporters only feature

Saturday 27-Jul-2024

... by: Hellmut Doll, Germany

Printing a Killer Sudoku is not possible. Only the numbers and letters of the rows and columns are shown and printed. Can you help me?

Thank you!
Hellmut

Andrew Stuart writes:

I see the problem.
Try now or use [CTRL]+[F5] to refresh

Tuesday 23-Jul-2024

... by: Jammy, UK

Found a grid that the solver couldn't solv

Not sure if that's feedback you want, but thought I'd share. I worked out that the 2x2 cage of 21 couldn't have a 9 in it, because it _had_ to have an 8 in it (only 8s in the middle nonet), and the combinations couldn't include both an 8 and a 9. After that, it could solve it.

Andrew Stuart writes:

That’s a good observation. I’m hoping I can put all these clues together and get some more completeness to the solver. I do know that the hardest puzzles have a bout a 50/50 chance to solver. Still a lot to learn. I’ll add this to my research tree

Monday 22-Jul-2024

... by: Daxx, UK

https://www.sudokuwiki.org/killersudoku.aspx?bd=5g0049012000003p01002i02014i0202015g4102026g3h01011i00010000003j030302000132710101010102213g024800005r03030100025h01010350000100491g00004100005i010132020201010202,h08060m00q0q0i3004h008060iu4k4sic03060060gu0d454c208s0081gv0vgvmlmv006s06030v6vuvuluv0060o8k1mv6vuvuluv0f00o8k3ka0l0l054088g028gg00c0e0ea0f0fg500240181o1oa004g0a0

TAKE STEP produces:

Simple Colouring
(RULE 4): Uncoloured candidate 7 in E4 can see two different coloured candidates of 7 elsewhere.

Then STOPS (Take Step is grey, [<<] Back step works okay)

Andrew Stuart writes:

Fantastic report ty. I’d not tested simple colouring in Killer and there were bugs.
Refresh now, you should see 2.24.3
Also the packed link was bugged, fixed that, example should load now

Sunday 21-Jul-2024

... by: Sam, US

I can't edit the candidates. I changed the values in the box, but they reappear when I click out of it.

Andrew Stuart writes:

Untick "Auto-clear"

I think I'm going to pop up an alert for this situation

Saturday 20-Jul-2024

... by: chris, Scotland

Your Send To Solver button isn't working.

Andrew Stuart writes:

Beg your pardon, didn’t upload all the updated files last night
[CRTL]+[F5] and refresh. Should work now

Saturday 20-Jul-2024

... by: Dan, United States

killer Sudoku not loading

Andrew Stuart writes:

Beg your pardon, didn’t upload all the updated files last night
[CRTL]+[F5] and refresh. Should work now

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Thank-you everyone for all your questions and contributions.