# 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 andrew@str8ts.com.
**Post a Comment or Question here...**
## Thursday 14-May-2009

## ... by: Mrs Peel, Arizona

Many thanks from this part of the country.

Phil Zell

Thank you Phil, great to receive such positive comments.

Best of luck with your solving

:)

## Sunday 10-May-2009

## ... by: Rod Nash, Australia

Thanks

Thanks for the prompt :)

## Friday 8-May-2009

## ... by: SGC, China

Load Sudoku: CLICK TO LOADhope you fine much more strategies.

thanks!

Nice one. Will have to work hard on this. Where did it come from?

Appreciated

## Wednesday 6-May-2009

## ... by: ECC, Oregon

Load Sudoku: CLICK TO LOADEasiest_Sudoku_Competition

Its just for fun and kudos, as I say. More entries to come I hope!

## Tuesday 5-May-2009

## ... by: Joe Read, Anaheim, CA, USA

Load Sudoku: CLICK TO LOADI got as far as the above situation, and asked for the "next step." I was given a Y-Wing with 8 taken off D2 and H1 using D1 G1 & H2.

I don't understand why that situations allows the 8's to be taken off D2 and H1 instead of being taken off D1 and D2, thus allowing them to remain on D2 and H1. In other words, 8's are in all four corners, so why are D1 and H2 selected as the pincers??

Thanks in advance for any insight you can provide. -Joe

There are two Y-Wings: D1-G1-H2 and D2-H2-G1

The first we know about takes 8 off D2 and H1

But the second one the pincers are made from candidate 6 (not 8) and these remove 6 from D1 and J2. There are no other valid or useful Y-Wings.

Both of them work and they give the same result: D1=8 and D2=6

You may have been thinking the 8s could be used in all four cells, but it’s the 'C' candidate that does the eliminations (see the theory diagram), which is 6 in the second Y-Wing.

As to why the first was highlighted that is down to the search order of the algorithm. It will only return the first successful example of each strategy. I would like to enable the solver to allow you to skip the first and look for the second but it might complicate an already complicated page to allow this.

Tricky position, I had to go through the logic very carefully as well.

## Saturday 2-May-2009

## ... by: Roy, Australia

Have you considered allowing visitors to input their own shapes in your Jigsaw Solver? This would expand its use considerably. Please do consider it.

## Monday 6-Apr-2009

## ... by: C David Allen, England

Load Sudoku: CLICK TO LOADI think you made a mistake on entry - which is odd because the sudoku you record in the feedback is fine. It grades as tough, and solves quickly. Have another go:

Best regards

Andrew Stuart

## Sunday 5-Apr-2009

## ... by: Andy, Germany

today i´ve got an update of my opera browser from v9.63 to v9.64

Now there is a Message in the Box under the Sudoku which shows a link to load the SudokuSapi.dll file.

I found a thread at the opera-forum (http://my.opera.com/community/forums/topic.dml?id=250917) where you kindly find a solution of this problem.

Maybe there is a problem with opera v9.64? I have v9.63 running on my second computer without problems. And i will certainly not upgrade ;o)

After that "bugreport" i have to thank you very much for your great job at this website. Me and my daughter solve Sudokus on her Nintendo DS and after many hours with your excellent stategy documentation, we can solve the puzzles much quicker now :o)

Have a good time!

Andy

If anyone reading this who is familiar with Windows 2000 and IIS, drop me an email. I'm not getting a result so far.

## Friday 20-Mar-2009

## ... by: pjs, california

## Thursday 19-Mar-2009

## ... by: E MACHIN, ENGLAND

THANKYOU ANDREW.

## Tuesday 17-Mar-2009

## ... by: patriotkiller18, usa