Community Puzzles Issue 8

First of all. it's great to hear we have a brand new Community Puzzles editor (sounds as though you've thrown yourself into the job Dave!) I thought it might be fitting to give a bit of feedback on the puzzles in the last issue - a fabulous selection by the way. (To think I only ever used to do straight forward sudoku!)

New Year's Day - I normally only do number puzzles but enjoyed this one for a change

Slithery Sum Sudoku - unfortunately I can't get started with this one Dave (nothing wrong with your puzzle, just my brain!) so if anyone has any tips, please let me know - I can be sometimes slow to pick up new puzzles until I've had a few goes and got the rules firmly entrenched in my mind. I've visited The Griddle many times since getting ths magazine and had a go at many of the puzzles, my favourites being the (Shapely) Alleyways and Skyscrapers (just done the last bunch)

LITS - I'd never come across this one before and once I'd got to grips with the rules I really enjoyed it, so much so I've visited Grant's site and printed off a few more (including a couple of giants which I shall attempt to have a go at!)

Fillomino - this is a work in progress at the moment - a bit bigger than ones I've done before.

Sudoku Minus - we've already had a discussion about this on another thread - also enjoyed the ABCD, not done the Square Numbers yet.

Deficit/Surplus sudoku - fun puzzles, not too difficult.

Sudoku Islands - I love the idea of this one, but not being very good at nurikabe it's driving me insane!! I've had three attempts so far and only got about half the grid filled in! Must print out a couple of easier ones from Tom's blog and see if I fare any better!

So, all in all, a brilliant selection of community puzzles - trouble is I have had to buy a storage box to put all my magazines and printed sheets in (the end of my settee was looking a bit of a nightmare!!)

I don't want to steal Dave's fire but I can give you a few quick hints about his Slithery Sum Sudoku puzzles! The one I put first is in my opinion the easiest because for this one you can solve the entire Slitherlink first before starting the Sudoku part, which simplifies the logic somewhat. Then the way to progress is to think about the 'biggest' and 'smallest' parts of the numbers first. So for biggest, if there is say a total of 5800 then clearly there must be one four-long region and the first digit in that four-long region MUST be a 5, because there's no other way of making a number big enough. And then if it ends in say 9 and you have two numbers in that row then the last digits of those numbers must be 6 and 3 or 5 and 4. I'm making those examples up to show you the two 'easy' sorts of logic you can use. It's definitely not about difficult maths! (which was my initial thought when I first saw them - but aaaargh soon became aaaah! ).

Thanks for the tips Gareth - I've been having another look at these since writing my previous post and to be quite honest, came to the conclusion that the most difficult part about them was doing the slitherlink loop in the first place (that and nurikabe not my best puzzles - masyu and yajilin much easier!). In the end I cheated a bit and looked at the answer to fill in my partially completed Slitherlink, and then managed to play around with the numbers (using the logic you mentioned) and filled in the numbers without cheating! Just done the first one so far. Now for the next two ...

Great idea for a puzzle Dave - don't know how you think them up!!

For the second and third puzzles you can't complete the Slitherlink without working back and forth with the Sudoku part of the puzzle - there's no unique solution if you completely ignore the Sudoku part.

Glad to hear the feedback Christine, and thank you for posting a bit of help Gareth! I've actually just posted some new Slithery Sum Sudoku today, all 6x6, but might make some smaller and simpler ones soon as well.

I'm glad to hear that you like the alleys & skyscrapers puzzles Christine, and will make more for a later issue and for The Griddle. As for issue 9, I've created a sudoku variant that I haven't posted before called "Lying Sum Sudoku" that I hope to include. I'm also planning on designing a separate copy for Sudoku Xtra since I've noticed my puzzles don't mesh well with the style used throughout the rest of the magazine.

I also enjoyed LITS, and am happy to say there will be another one this issue. Grant has also included another Fillomino - and so has a new contributor. Actually, the majority of the contributions this month are of types not seen before in Sudoku Xtra, so I'm not sure how well you'll like them. I will however take into account your favorites when asking about content next issue!