... by: jar29, perth, australia

thankyou for setting up this site. i was ready to top myself if i hadn't solved that bloody puzzle. i'm sure i will be back. have fun

... by: Leon Heckman, United States Boston MA

Load Sudoku: ....8....48...2...9326.58746.58...2...4..9......1.67.8..6..8...748.9..612......87

Andrew,

Lately, I have become interested in Sudoku because it is printed in the local paper and I try to solve the puzzles on my train ride to work. I can solve many of the puzzles but I get stumped on many as well. So, I found your excellent website to improve my skills. I also bought your book and I am wait for its arrival.

Now my question:
I found a website that generates Sudoku puzzles that can be printed. I selected a moderate puzzle since I am trying to learn the process. I printed from this site.
http://www.yourfungames.com/games/sudoku/moderate17.php

After working on a solution for many hours, I gave up and entered the puzzle into your application. Your application cannot find a solution either.

I don't understand. Maybe you can help me.

Leon Heckman

Andrew Stuart writes (11-Dec-2007):
Hi Leon
You are the victim of an unscupulous sudoku web site. Use the link in this posting to reload the so called moderate 17 from that web site. Press the "Solution Count" button. You will see it has 51 solutions. These people don't know how to make sudoku puzzles. Logical strategies only work if there is only one solution.

yourfungames.com is probably just an advertising revenue web site. Certainly looks crowded with ads. Yuck. If you want some real puzzles go to www.sudoku.org.uk

... by: Judy M., Alaska

The Sudoku Solver is particularly spectacular, thank you for this amazing website. I did notice that if my browser, IE, has cookies blocked, and I click "Save", the msgbox mistakenly reports that the puzzle has been saved when it has not. It would be great if your code checked for blocked cookies before reporting whether the puzzle has actually been saved or not. Overall, perfection and huge value to puzzle enthusiasts!

... by: Carmen Martinez, Spain

Load Sudoku: 4.126.5..6.......22....74.6.16...85....68.2.1.8231.64...48.6..5........88.75319.4

I couldn´t continue with this Sudoku, so I put it in your helper and after it wrote several numbers a legend appeared saying something like there were no more theories to resolve this sodoku. So I looked at the solution in the newspaper and the numbers that the helper wrote were wrong. All the numbers the helper wrote were based in the different types of Unique rectangles. Does this mean the unique rectangles can sometimes be used and others not ?
Thank you very much for all I´ve learned with you ,and excuse my english for I am spanish.
Andrew Stuart writes (4-Nov-2007):
Carmen, please click on the yellow Solution Count button on the solver page. My solver finds 162 solutions. Unique rectangles are only a valid solving tool for sudokus guaranteed to have one solution. Most likely, you omitted one or more of the givens when you entered this sudoku into the solver.

... by: Ron M, Australia

Congrats on the best help I have found. One basic question- how can I fit your whole page of solution on my screen. Annoying to manipulate every time to fit all page in-probably a 70 yo technophobic
Regards. Ron M
Andrew Stuart writes (30-Oct-2007):
Glad you like it. You need to change your screen resolution from 800x600 to at least 1024x800. Unless you are running a very old computer/monitor this should be perfectly position. Find a blank area on your deskyp and right-click with the mouse. Choose properties. Click on the settings tab. Increase your resolution.

... by: Chuck Bruno, Virginia

First of all, I would like to thank you for this great program. It is a wonderful aid and learning tool. I have a suggestion that I think could be useful.

For the various stratagies listed on the right side, in addition to being able to turn them off by removing the check mark, how about being able to re-order them by changing the number of the stratigy, perhaps by putting another box for the number just to the right of the checkmark box. What do you think?

Thanks again for this extreemly useful program.

Chuck Bruno
Andrew Stuart writes (28-Oct-2007):
You are not alone in suggesting this and its something I'd really like to add. It would significantly complicate the user interface which might put of casual users and beginners. However my ordering is subjective. It is based on my personal comparision of the complexiity of the strategies but it should be open to anyone to re order. It would help find other solve routes. In the job queue

... by: CES, USA

Load Sudoku: 020510040080060102001008360200300781895040623173006004732904016409070230008032479

The program came up with a "blocked" messsage a couple of days ago and now it is stuck on xwing in the solution.
Andrew Stuart writes (4-Nov-2007):
The tough and higher strategies execute on a server running a program written in C++. Your computer transmits the sudoku to the server and it returns results. Your computer displays wait until results come back. Sometimes internet congestion, server overload, etc., prevent your computer from receiving results and the wait remains indefintiely. When that happens, reload the solver page and try again. This sudoku solved when I tried it.

... by: Harald, Bavaria

Load Sudoku: 00059008370000200500300000080067000400600050090008500700000020060070000935004900

The simple colouring step which gives "SINGLES CHAIN (Type 1): Removing 1 from F2" colours the locked pair "13" in column 6 which has nothing to do with this chain.
Andrew Stuart writes (22-Oct-2007):
That's true if you are thinking just of chains - which is the alternative strategy, but with simple colouring one is colouring all cells and seeing which of them can be made into chains within that set that lead to an elimination, so its important to show and see all the cells that can be coloured. There might be two or more independent eliminations through colouring (although my solver will only pick/show the first)

... by: Justin, Massachusetts

Load Sudoku: ...792.8.9..6.57..7......95..8....14..9.5....46.....9..5.......1..45.1..9.9.27...

This is from the 10/13/07 Tough puzzle at sudoku.com.au.
the following eliminations have been made:
45h not 7, 23b not 8, 9c not 6
When I put it into Sudoku Solver and step, it gets down to Xwing and goes to sleep, saying Wait.
I've used this excellent program many times before without any problems, so I don't think the problem is in my system.

Andrew Stuart writes (17-Oct-2007):
I Justin, I think the server had hung when you were using it. Should be ok now, but your sudoku example is not correct. May numbers the same in rows and columns

... by: cbee, Malta

Can't think of a single imporovement. Its a great program I use every day. Keep up the good work.
Andrew Stuart writes (17-Oct-2007):
Many thanks! appreciated

... by: Jacques Bourgeois, Switzerland

Hi,

Thanks a lot for your solver, it saved my life.... We tried several hours to solve some sudoku with my son which have soon a test at school. We are not experienced with sudoku and don't know all the techiques. We solved several sudokus but the last one didn't want to reveal its secrets. Looking for help about sudoku strategies we found your site explaining several of the strategies and ITS step by step solver. Using this one we could very easily understand the underlaying techniques and now everything is ok.

We congratulate you for you very well constructed site.

Best regards,
Jacques Bourgeois