SudokuXtra Issue 13

I have finished issue 13 and not a gremlin to be found! I really enjoyed it as usual and especially the second two Skyscraper Zeros in the community section which I found difficult and frustrating but challenging and fun at the same time. The addition of the zero gave the puzzles a very interesting twist.

I also liked the Mirror Box and the Pentomino Queries-once I realised the letters on the outside were not necessarily in same order as the shapes appear in the puzzle! [Until I realised that I thought I had come across the first gremlin.]

I do so enjoy this magazine and, like christine said in another thread, like having the variety of puzzles to keep me interested and stimulated. I do hope there are enough like minded people out there who know about SudokuXtra to keep it going for a very long time!

Now eagerly awaiting Issue 14 Gareth!!! In the meantime I am doing some puzzles from the sites in the community puzzles section and I'm going to have one more go at Tiger in The Woods-which is still defeating me.

p.s. It's very quiet on this forum at the moment but perhaps that's because Issue 13 was so perfect.

Hi Nikki, well done you on completing the magazine! I am really impressed that you have managed to complete everything. Have you ever thought of going on the Logic Masters India site and doing some of the weekend competitions? Give some of the men a run for their money!!
I've done about as much as I can do of Issue 13 now which is about 80% of it as usual! I keep going back to old magazines and filling in the odd gap and it is my ambition to one day have every puzzle of one of the issues completed!!

I enjoyed all the old favourites - consective, odd/even (I'd love another samurai odd/even at some point now we are more used to them), the skyscrapers, loop puzzles, labyrinth I also enjoyed the Zero Skyscrapers although I haven't managed to crack the Zero X yet (got quite a lot of 6s and 7s in but drawn a blank after that, but I haven't given in yet. I've got addicted to the Krypto Kakuros now and have visited that website and run off a couple of the booklets!

What I have completely drawn a blank with are the Heyawakes. I simply can't see how to get started on these ones! So if I could put in a request for a few simple ones at some point to get used to them (I suppose someone might tell me the Issue 13 ones were simple!!) that would be great or if anyone had the time to do a walk through of one of the puzzles or just some more hints and tips that would be great.

Like you Nikki, I hope there are enough like minded people out there to keep the magazine going for a long time. Good luck with Tiger in the Woods (they are part of my 20% non-do-able puzzles!!)

The Heyawakes are pretty tough, I agree. I had great fun making these!

Here is a clue to get you going with the 8765 one on page 13. Look at that 7. It has to be a 'zip' pattern running one of either two ways. Either way it goes, however, the adjacent squares on each side in rows 1 to 6 must all be empty.

Now look at the 6. The top 4 rows can only have 2 shaded squares now, so the bottom 4 rows must have an alternating zip pattern too. But that zip can only run one way else no matter how the 7 is it will break the puzzle into two white areas. Once placed you can now put in the other 2 squares in the 6, and indeed the 7 can now be completed.

At this point you can reason about what must go in the 5, and place much of the 8.

Does this help? Is this explicit enough?

And here's clue for the bottom puzzle on page 13. Look at the corner '4's. There is only ONE possible solution to each of these 4 areas. If you place these that should get you going. You can also use similar 'zip' logic around the edges of the left-hand 5 region to mark some squares as definitely empty.

Finally, the big cover Heyawake. Here's a clue: start with the touching 0 and 5s right smack in the centre of the puzzle. You can place quite a bit here right away, and then the puzzle solution ripples out from the centre both anticlockwise curving out and clockwise curving out, finishing where they meet somewhere on the lower left.

Hi Gareth - thanks for taking the time to type out all those hints for the Heyawake puzzles. Much appreciated although I really don't think Heyawake is going to be my forte! I still haven't managed the cover puzzle and only managed the smaller ones by printing out multiple copies and filling in the zip patterns both possible ways and following them through until I got stuck again. I finally got a solution more by trial and error than by logic. Still, at least I've got one or two more strategies to use now if ever I feel the inclination to try and solve any more of these, but I donlt think they are ever going to count amongst my favourite puzzles. Never mind, plenty of other types to go at.

This is the first of the SudokuXtra booklets I have attempted - introduced to them by Dave Millar (thanks Dave!!!)

I have not really enjoyed Heyawake puzzles prior to attempting the ones in this issue as I usually have had a lot of difficulty getting started with them. However, I really enjoyed these ones - particularly the cover one. After a few false starts, I realised some of the obvious things I was missing regarding the 0 and 5 and edge cells and so on, and found (as you described above) that it flowed both ways from there. This led me to insights about the puzzles generally, so now appreciate them much more.

I didn't realise that you had posted hints for them, so am extra pleased to have worked them out without needing the hints. Unfortunately, I am not having as much luck with the Samurai Star which I have attempted a number of times, only to end up with conflicts towards the end of the puzzle. That's OK though, part of the problem could be that I am only doing these on the train trip to and from work, so it can be difficult to concentrate at times.

One of my favourite puzzle types is (currently at least) slitherlink, and these were enjoyable... and most of all the giant one in the member contributions section. Awesome!

Quote
Maree Cassidy
I am not having as much luck with the Samurai Star which I have attempted a number of times, only to end up with conflicts towards the end of the puzzle. That's OK though, part of the problem could be that I am only doing these on the train trip to and from work, so it can be difficult to concentrate at times.

I had another attempt today on the train trip, and solved it. I have no idea what I was doing wrong the last few times

Well done on the Samurai Star. They're a lot quicker once you spot how each triple of 3 numbers repeats every third block of three numbers.

I'm particularly pleased you enjoyed the heyawakes - I tried to pick a different theme for each of the smaller puzzles which would help with solving the larger one at the front. I was pleased with the 8765 numbering too.

Interestingly, I only attempted the smaller ones after solving the cover one.

Regarding the Samurai Star... I already had the repeating triple notion, but still somehow managed to botch it three times before getting it right.

Hello Gareth and Maree

Re samurai star - I love these too and usually do them first! However the one in this issue, I think, has 2 possible solutions. This is very unusual for you, Gareth, so maybe its me that's wrong. I too got stuck at the end with alternate choices in about 20 cells and could not find any logic as to which choice was right. After quite a lot of puzzling/checking I just opted for one choice to see if it worked and it did. Not a very satisfactory way to finish a puzzle really. I was curious about this so checked the official solution which was was different. I tried my choices the other way and I came up with Gareths solution. Perhaps this is what you found too Maree.

The conflicting choices were mainly beween the placing of the 9's and 8's. I opted for a 9 in the 3rd cell so my line 1 reads 129 647 835 and the rest fell into place from there. I keep looking to find an error somewhere but haven't seen it yet.

Oh well it keeps my idle mind busy!

Sue

No, I actually botched it - ended up with 8's or 9's unable to be placed.... maybe for a very similar reason. I haven't checked my solution against the official one. Will have to though later.

Hi Sue, Marie, Gareth..!

I hadn't actually done this puzzle but having read the above posts decided it was about time I did! I have to say that (unusually for me!) I managed to do this first time, and that it all seemed to fall into place quite logically. I checked the solution and it agreed with the answer given. Whether there is more than one solution I can't say (I haven't tried to find another) but no problems with it as far as I could see.

Quote
sue
The conflicting choices were mainly beween the placing of the 9's and 8's. I opted for a 9 in the 3rd cell so my line 1 reads 129 647 835 and the rest fell into place from there. I keep looking to find an error somewhere but haven't seen it yet.

I can guarantee that there is only one, single solution to this puzzle, and it can be reached with straightforward step-by-step logical deductions.

Sue, if you'd like to send me a picture of your puzzle (gareth@sudokuxtra.com, or post it here) I can find the contradiction? I've just rechecked this by hand, but in fact the Sudoku puzzles are all checked automatically by computer and solved via two different methods, so the likelihood of an error is really low - I've never had one yet!

Hope this helps resolve the mystery.

Hi Gareth

I don't have the technical means to send you a pic of my (probably wrong) solution. No doubt there is an error in there somewhere so will re-check when I have a spare moment. I don't usually have a problem solving these and this one seemed to fall into place quickly so probably I made a mistake in my haste. Will return, no doubt shame faced, later! Thanks for response.

Sue

PS Just got your spam question wrong too..... read the question Sue! Think I'd better go back to bed.

Sorry about the spam question... I don't understand why it appears sometimes and why not other times (when logged in), but I don't dare disable it in case the forum gets overrun with spam! You're welcome to post me the sheet if you like?

Hi Gareth - no it was me who got the spam question wrong as had misread question! How shocking for a Maths teacher. Kill me now!

Anyway, have now looked again at my solution and found my error - it wasn't obvious. So sorry to have caused you some work. In my defence, I did say it was probably me that was wrong. I do tend to go too fast for my own brain sometimes. Careless again.

I bow to you and Christine's superiority. Looking forward to new issue now. I might even have completed the samurai star skyscraper by then! Does anyone else find these difficult or have I missed something. I love these - always a great challenge but I leave them until I know I am going to have plenty of free time.

Sorry again from careless Sue

Hi Sue - it's nice to know I can get one over a maths teacher occasionally!!! Only joking - it's usually me who's the one asking for help.

I'm not so successful with the samurai skyscrapers - I find them difficult too - I've only ever completed two or three of them, but I love having a go - I'm always going back and printing them off for another try. What a buzz when you do finally get one (occasionally!)

I'm also looking forward to the next issue - trying not to be too impatient.

The Samurai Skyscrapers are very hard - there is no shame in not being able to complete these!

Or put it this way: Skyscrapers are one of my personal nemeses! I've seen people solve the regular ones in about 30 seconds, on the same puzzles that take me several minutes...

Meanwhile, issue 14 is finally available! See the Announcements forum for the full details!



Edited 1 time(s). Last edit at 04/08/2011 11:21PM by gareth.

Hi Christine - not the first and no doubt not the last time I have been bested! I did finally (3rd attempt) finish the samurai sky so thought I'd come on here to brag! I'm glad to hear it is possibly a universal challenge and not just something clever I have missed, but, like you, I always love trying them. One of my favourites despite erratic success rate.

Off to download 14 now.... thanks as always Gareth,

Sue

I love Samurai Star Skyscraper, it's usually the first puzzle I do in each issue. It should come as no surprise that I prefer tough puzzles!