Feedback and Questions

I like doing the 4x4 grids with 0-9 and a-f options but I hate filling in all the cell options as it takes forever. Do you have an x-cel formula that will fill in the missing numbers for each cell. I like doing it by hand so I would just print it out.

Thanks for the help.

If I try to solve this sudoku there is only found a hidden pair but then there is nothing else...
Is it impossible to solve it by logic steps?

The Jigsaw solver is very helpful as well as educational. Helps to see the various stategies in action. Could you set up another pattern for the regular Sudoko (3x3's within the 9x9)? The basic Sudoko helper doesn't go into many of the advance techniques or explanations that I found most useful in the jigsaw solver.

Andrew,

I'm trying to get my mind around both of the "Y Wing" strategies. I've tried to understand all of your examples but I cannot seem to understand the relationships. I've seen some ot these in some of the puzzles that I've done recently. And after I felt that I knew what the possibility was I checked the answer sheet and I was right, but I don't understand why. I just see the possibility.

Can you help me better understand this strategy?

Richard

Do you have a date for the publication and availability of "The Logic of Sudoku" yet? I remember first hearing that it would be out around the end of November. What is the current status? Thanks.

Richard Proctor

Andrew,

Your Jigsaw solver is a nice tool. However, I would like to suggest that you consider changing the order of the basic tools from:

1: Singles in Row/Col
2: Singles in Box
3: Naked Pairs/Triples
4: Hidden Pairs/Triples
5: Naked Quads
6: Pointing Pairs
7: Box/Line Reduction

to

1: Singles in Row/Col
2: Singles in Box
3: Naked Pairs/Triples
4: Pointing Pairs
5: Box/Line Reduction
6: Naked Quads
7: Hidden Pairs/Triples

The order of revised order of 1-5 are pretty arbitrary, but I suspect that these 5 steps are used by most players to find eliminations before they ever start looking for Naked Quads or hidden pairs or triples. Without aid, I have successfully used ALL of the first 6 steps on a regular basis. Perhaps, I have RARELY found a hidden pair. I don't think that I've EVER found a hidden triple - without someone (or a program) pointing it out to me.

When I press the botton 'Take a step' for the puzzle Escargot, it just appeared the sentence 'Run out of known strategies.' after I pressed the botton for a few times.

Assume that a sudoku contains an error. You use as condition for stopping that there are to cells containing the same value in the same row, column, or box. However, in some cases all candidates get deleted from a cell, but you never get two cells containing the same value in the same row, column, or box.

The attached sudoku has this properry.

The solver should report an error, if all candidates are deleted from a cell.

It's just a small thing but I was looking at the explanation for the X Wing strategy and you refer to square "G7" but the board is only numbered for both rows and columns so there's no "G".

I love your site. But I have one problem. When I click the "go back one step " button, I go back 4 or 5 steps.