Feedback and Questions

I was trying the Escargot sample from your page and it seems the solver runs out of strategies. However, your solution counter does show that there is exactly one solution. Is this a known issue?

Hi Andrew,

I found this Sudoku X in a German magazine called "Sudoku Logisch Spezial" (Issue No. 14 from June 2008).
Some cells of the grid are restricted to even numbers. These are C7, C8, D3, E5, F2, G1, I2 and I7.
The difficulty is rated "easy"... *sigh*
After spending some hours I gave up, tried again some weeks later and so on - until today.
I remembered your web-site and wanted to be shown what I have overlooked and I the end it claimed "Run out of known strategies."

For you are interested in examples that can't be solved on this page I sent this to you. The SolutionCount-Button did not work! ("Not available just yet")

I don't know whether there is a solution derived from any strategies, maybe it is only a misprint, but the given one on the last pages of the magazine is this:

258634791
794512386
163789245
936145827
572863914
481927563
617258439
849376152
325491678

Apart from that I just can say that this homepage is a great benefit when stuck in a puzzle.
Thanks a lot.

Absolutely fantastic. Must have cost you a lot of work, how generous to share. Many Thanks.

Finally, an explanation and example of the X-wing I understand. Thank you.

wow! this is nice! great job Andrew !

Hi Andrew,

I'd like to put in a plug for a feature. I tried using the save and restore feature on your regular solver page "http://www.scanraid.com/sudoku.htm", and the results were nearly what I had expected. Any solved squares in the saved cookie were restored.

My request is to make this feature much much more useful. I actually use your solver as an aid (an online blackboard mostly) to hold the candidates for each cell, as I work on solving "Killer Sudoku" puzzles. I click on each cell of a cage and enter the possible candidates as restricted by the cage values. What I would like your SAVE function to do, is to save all the candidates from the screen to the cookie, and restore all the selected candidates when RE-LOAD is selected. If a sell is "solved", it will only have one candidate, if it is unsolved, it will contain 2 or more candidates. This could be accomplished by using a comma or semicolon separated list instead of just a list of 81 digits/characters. Since my reason for asking is so that I can save the state when I'm working a puzzle, or stuck and want to return later, the major work in getting back t where I was is resetting the candidates. The current RE-LOAD function is useful, but f makes me re-eliminate all the candidates that I've already eliminated in prior work.

Thanks.

-Carl

After sporadic attempts to solve Sudoku puzzles in the LA Times I learned some very basic strategies but there's a limit to how accurately you can work using an erasable pen and the original printed puzzle (!).

So I turned to Google and after looking at a few sites I came across yours - and a welcome breath of fresh air :)

Congratulations on the work you've done - this is an excellent tool for newcomers and old hands alike IMHO. I know my skills have certainly benefited greatly from it. More power to your elbow!

Andrew, Is a puzzle possible in which the two diagonals (A1 to J9 and A9 to J1) are also unique 1 - 9 numbers? If so, please post it in at least a "hard" format. Thanks

your page is an excellent resource for solving difficult sudokus and learning the complex stategies.

i have a question and i don't see it in the strategy explanation. how does the hidden unique rectangle work? when i was rying to solve a puzzle, one of the steps involved the hidden unique rectangle.

mahalo,
rod

Hi Andrew,

This is a great site! I am wondering what the score is of the most difficult sukoku that your solve can solve? And do you have this sudoku as an example?

Cheers,

Ygor