Errors in Issue 12

Sudoku Xtra 12 was my first issue. It's starting to look like my last as well: I just contacted David Millar separately to let him know his page 43 puzzle is missing a very important instruction, and I was satisfied with his response, but I just encountered another error, in the main section this time - the Hitori on the bottom left of page 7 has two solutions. The given answer (on page 56) is one of them, but toggle the two fives on the second row (from the top) and the two fives in the leftmost column, and you have another working solution. Given I've only started work on six pages out of fifty-four and already found two errors, I'm not exactly having high hopes right now.

- ZM

P.S.: Was the "[+1]" puzzle on page 16 entirely necessary? If this were an April Fools issue, I'd understand why it's there, but for a Christmas issue it's just obnoxious. I do hope you'll forgive me for subtracting the number of cells in each cage from that cage's total and then just solving it with the standard set of values. It would be nice if future variants were actually, you know, a VARIANT, rather than the same puzzle with a pointless layer of abstraction that changes nothing. (The negative values for the page 26 puzzle affect subtraction cages, at least...)

Hi Zotmeister, I am sure Gareth will respond to your comments, but after reading your post I just couldn't stop myself leaping to the defence of my favourite puzzle magazine! I have bought every issue so far and will continue to do so as long as it is published. I do appreciate that everyone wants accurate puzzles with only one solution, but also accept that occasionally mistakes do occur, and to be quite honest without putting myself down (because I'm not!!!) I had solved David Millar's puzzle without noticing any missing instruction, and as far as Hitori is concerned I'm quite lucky if I get one solution, never mind looking for a second one! And although the +1 puzzle wasn't "entirely necessary" it was simply a bit of fun to do the same variant with a slightly different range of numbers - not overly diffiicult on this occasion, but just a slight change to add a bit of interest.

Which leads to the main point of my post. What Sudoku Xtra provides is a unique magazine for the likes of myself who have gone beyound the realms of the popular sudoku magazines to be found in the local shops and are now seeking to challenge themselves and learn new puzzle types. We are perhaps above the level of the average solver (i.e. those who do the odd few puzzles that are published in newspapers etc) but will never be able to reach the levels required to compete successfully in international puzzle competitions etc. There are separate sites for those - I did start to post on one such site a little but soon found myself out of my depth, but that is fine - specialists will want to discuss at their own level.

I am probably rambling off topic now but just wanted to re-iterate that Sudoku Xtra is the only magazine I have found which caters for the "in between" puzzler, if that makes sense. At my level of puzzling, some of the puzzles are easy, some require quite a bit of thought, some are positively challenging (but give a great sense of satisfaction if completed) and some I simply cannot do (one or two in the Community section) but I always enjoy trying out new varieties and each issue there is usually something new which captures my interest and I have a new puzzle type under my belt. (There could be a separate discussion on what makes one type of puzzle quite manageable and another one you haven't a clue where to start!)

Sorry if I went on a bit, but Sudoku Xtra is a passion of mine and I'm already looking forward to Issue 13!

I wasn't "looking for a second" solution - I was trying to deduce just one. Such is the expectation of a logic puzzle. When there's more than one solution, it can't be solved deductively... you'll get stuck, because at some point there is no "next step" to be taken. As you seem to have noticed, Hitori is hard, even at small sizes, so a broken Hitori is particularly expletive-worthy, especially when it's been paid for.

I think you missed my point on the +1 puzzle. Let me remake it from a different angle: there's a Killer Sudoku "Prime" in the sample issue on the site here - the sample issue is apparently based on issue 8, so you should have seen this. Instead of 1 to 9, it uses the primes from 2 to 23. This puts great gaps in the range and really changes up the puzzle. That's a proper variant. But the +1? That mathematically changes nothing. All he did was take a usual Killer and add one to every cell. It's no different from the standard version - it's a joke puzzle, and the joke isn't funny.

And as for Dave's puzzle, you've probably solved other Sum Sudoku puzzles in all those other issues, so I doubt you even noticed nothing was said in the rules about those dominoes in the grid... I'd never seen a "Sum Sudoku" before, and there wasn't another one in that same issue, so there was nothing to tell me about the vast majority of clues in the puzzle. Dave implied that he should have printed it with Killer-style cages, making them look like the puzzles in the main section; if he renamed the puzzle to Chess Killer Sudoku as well, that would have fixed it. Or he could have added the rule to the instructions. Either way.

I'm glad you enjoy the publication - I enjoyed the sample issue, which [along with Grant Fikes' plugging - I totally blame him ] is why I sprung for a full issue. I certainly wanted to enjoy it, and I was definitely expecting to enjoy it, but when I see a missing rule, a broken puzzle, and something I can only diagnose as an intentional annoyance one right after the other, then I hope I can be forgiven for not finding it enjoyable. - ZM

Hi again, Zotmeister. Just wanted to make it clear that I totally respect your opinions even if I don't agree with all of them! Hitori is one of the puzzles I just don't happen to be able to do except at the most basic level so I accept that it would be frustrating to find a puzzle that has two solutions.

I do understand the point you are trying to make about the +1 puzzle, just happen to see it from a different point of view. In every issue of Xtra on page 16 Gareth publishes 4 Killer sudokus - 3 standard ones increasing in difficulty, and then one wiith a different range of numbers. As you point out, in issue 8 it was prime numbers, in other issues it has been negative numbers, or a mixture of negative and positive numbers, this issue it just happened to be +1, which no it didn't change anything mathematically, but for me personally it just made a change to have to remember whilst doing the puzzle that for example a 16 cage wasn't automatically going to be 9 & 7, but could also be 6 & 10. Not an overly challenging change in this particular puzzle but still more interesting to have 3 standard killers and a slightly different killer than 4 bog standard killers. I am always looking to see what Gareth has come up with for the 4th killer on the page, some are easier than others.

To be quite honest I never really thought about the instructions on Dave's puzzle - just looked at the broken lines and assumed that meant killer cages and went from there. I was a bit lazy about counting the numbers round the chess pieces so decided to see how far I could get by treating it as a normal Killer sudoku and I actually found I only needed a few of the numbers displayed in the Kings.

If I sound overly defensive it is simply because as stated in my previous post, Sudoku Xtra is the only publication to my knowledge that caters to that 'in between' level of puzzler and where I get most of my puzzles from. I often frequent the LMI site and have done one or two of the competitions but mostly find a lot of the puzzles unknown to me, or if more standard varieties I can't compete from a time point of view. Is it true that most of the world's top puzzlers have a mathematical or computing background? Just curious, I could be completely wrong on that one.

What has been great to see is that the community section of Xtra has been developped by Dave and now contains loads of puzzles from some of the world's top puzzlers (whose names I recognise from various puzzle blogs I read). There could be a slight danger here that some of the puzzles become too difficult for the likes of myself, but so far I've been able to have a reasonable attempt at most of them - perhaps a masterclass in some of the more difficult ones would be an idea...!

Anyway, I never meant to ramble on again at such length. It's a shame that this particularly magazine doesn't seem to be for you, but I hope despite your findings, there were still many other interesting puzzles in there which made up for it!

Hello Zotmeister

How disappointing to read your comments. I have subscribed and thoroughly enjoyed the challenge of every issue of Xtra. I have yet to find any ambiguity or error but I have not done every puzzle in every issue and have yet to attempt the Hitori as am not a big fan of these. I think you have been rather unlucky to have found problems in your first issue.

Like Christine above I am a huge fan of this publication and Gareth's puzzles in general. Something new each month and some really good challenging puzzles to get stuck into. I , too, think it is vastly superior to all other puzzle publications for experienced puzzlers. I'd give it another go if I were you.

I expect Gareth will join in this thread when he reads your comments.

Meanwhile, good luck with the rest of the puzzles..... I hope you enjoy them and find no more problems

Sue

Hello ZM and all.

ZM - I agree with many of your comments both here and by e-mail, and I'm sorry you had a negative experience with Sudoku Xtra. My role as an editor extends only to the community section, so I'm afraid I cannot speak to the multiple-solutions issue with the Hitori puzzle that you found.

I can, however, address the Chess Sum Sudoku puzzle problems. There are no great excuses I have for the problems you found, so instead I'll highlight the changes I hope to make in issue 13 for my next Chess Sum Sudoku:

• Rename the puzzle "Chess Killer Sudoku" to match Gareth's naming conventions.
• Change the instructional text to either explicitly explain the sum clues or refer to the normal Killer Sudoku instructions.
• Restyle the grid and cages to match the style of Gareth's Killer Sudoku puzzles.
• Remove unnecessary additional clues during the test solving stage to make the puzzle more difficult.

Additionally, I'll try my best keep a close eye on instructions and styling of the other puzzles in Community Section to ensure that similar problems do not occur with the puzzles we feature by other authors.

Again, I'm very sorry to hear that you had a negative experience, but I appreciate the time you took to provide us with your feedback. I hope you'll continue through issue 12 and have a better experience with the rest of the puzzles within.

Christine and Sue - Thank you for the kind words about Sudoku Xtra. We're glad to have you as readers and look forward to providing you with more puzzle-filled issues in the future. While I'm glad to see that you had only positive things to say about the magazine, I still invite you to provide any feedback you think of while working through the magazine so that we can continue making the magazine better for everyone.

Thank you to everyone involved in this discussion!

David

Thank you very much for pointing out about the Hitori, and I'm very sorry it has two solutions. I can quite understand that you are upset about that - I know I would be too, as a reader. When I assembled issue 12 before Christmas I had run out (as of this issue) of my pre-made Hitori puzzles so I grabbed some from my first book of them I made in 2005 (puzzles 61 and 62 in fact). However back when I wrote that book it went through a couple of drafts before I sent it to the publisher, one of which had that broken puzzle in. It isn't in the finished book, since I found it when test-solving - in fact that "puzzle 62" from the bottom-right of the Hitori page in Sudoku Xtra 12 became puzzle 61 in the book and I made a new puzzle 62. Unfortunately I dug into the wrong folder when I pulled out those Hitori puzzles for issue 12 - I went to '.../puzzles' not '.../v2/puzzles' in my archive. Thus the broken puzzle - a very unfortunate selection. I say all this by way of explanation, not mitigation, in order to show that this is a freak occurrence. Every other puzzle this issue (other than the Hanjie) was freshly made for the magazine.

On the plus side, for any more general readers of this forum, if that's my first broken puzzle out of over a hundred magazines and dozens of books then I'm not too ashamed of that. You're welcome to any previous issue of Sudoku Xtra as an apology and if you find a significant error in one of those then I'll send you every issue for free (as you can see, I'm confident you won't find any errors). I'll also send you a corrected version of issue 12 and upload it here for anyone else to download (I'll post again when I do that). If after that you're still unhappy then I will refund your purchase price.

Re the instructions for the Sum Sudoku, I am sorry one of the rules was missing. I think David's replied to the detail of this point already so I won't repeat what he's said. I do always re-edit (usually entirely re-write in fact) and check the instructions for the Community puzzles, which are all very generously donated by their authors, including Grant Fikes who has been an absolute hero, but unfortunately in this particular puzzle I got rather distracted arranging the three different piece type instruction graphics and text nicely and evidently omitted to fully check the rules. As you observe, for the 95% of readers who are repeat buyers the full rules were in previous issues, but of course they should have been in this one too - at least the numbered cages were obviously unexplained so you could see immediately that a rule was missing and thus I hope not waste too much time. I make great efforts to have every page entirely self-contained so they can be printed as single sheets if desired.

You're not the first person to write to me about the +1 puzzle, so I can see that it arouses strong emotions, and I'm sorry it disappointed you. One of the reasons I put so many puzzles in each issue is because I know that not every puzzle will appeal to every reader. It is indeed a mathematically trivial transformation but I don't see any great fault in that. Isn't observing that part of solving the puzzle? There are countless trivial transformations of Sudoku, such as replacing numbers with letters, and while of course they have no logical difference the fact is that they do change the experience somewhat for a human solver. In any case if you look through back issues (or check issue 11 when I email it to you shortly) you'll see that every issue has a different set of numbers for that puzzle, and that's the first +1 selection. In my opinion it is preferable to have a +1 puzzle as opposed to a fourth regular Killer - perhaps you disagree, and of course you're welcome to do so.

I do sincerely apologise that your experience of issue 12 was not ideal, and you should have issue 11 in your inbox before you read this post.



Edited 1 time(s). Last edit at 01/10/2011 11:11AM by gareth.

If you have downloaded issue 12 please re-download it. Changes:

1) Page 7 Hitori fix, as above
2) Replacement Killer Sudoku variant puzzle on page 16 (now is one with no multiples of 3)
3) Added instruction line on Chess Sum Sudoku to make explicit the meaning of the sum boxes

If you have a printed copy please email me and I will send you a PDF copy so you can re-print these pages if you wish.