Friday, 10 July 2020

Friday Puzzles #303

So by now more or less everyone has heard of Cracking The Cryptic.  Lots of the puzzles featured these days are what I'd describe as curiosities, sometimes with strange mish-mashes of constraints paired together to produce interesting solving gimmicks, sometimes with constraints and solving mechanics that go way beyond anything that resembles classic sudoku.  In any case they represent sudoku variations probably wouldn't retain much in the way of interest once the initial novelty had worn off.  Not that it isn't great to see so many different people I'd never heard of before producing these interesting novelties of course!

One idea that does seem to have a few more legs appeared in a more fiendish form that presented below.  Ahaupt's idea is for you to construct an irregular grid from a regionless start to the puzzle, using clues which give the sums of numbers to be placed in each of the cells the clue sees in both the horizontal and vertical directions up to the border of a marked region, including the cell the clue is contained in.

I think the idea is perfectly nice if you are given the courtesy of the irregular grid to start off with.  You end up with something that is related to Jigsaw Killer, where you combine Irregular Sudoku with Killer Sudoku, but something that I think is a little bit nicer, and with enough differences to warrant calling it a separate Sudoku variation.  I'll call it Signpost Sums Sudoku.

The trade-off with Signpost Sums is that you no longer have the cages represented visually, which is a bit of an inconvenience, but you do have the comfort that you don't have to scan across different regions when looking at the sums, and you get the possibility of having some of the now implied cages to be overlapping.  As each of the sums are entirely contained within one region, it means that you still get to keep the no-repeats condition with the sums.

I've tried a puzzle using a normal 3x3 box layout, and whilst possible I don't think it was all that enjoyable.  Instead I've gone with a couple of irregular grids, one a warm-up, and one towards the harder end of difficulty you might see at a well-balance competition.  I'm kind of hoping I've taken enough care with the clues and testing this myself for these to have come out uniquely, but if not I'm sure one of my dearest readers will let me know soon enough.

    #345 Signpost Sums Sudoku – rated easy(ish)
    #346 Signpost Sums Sudoku – rated medium

All puzzles © Tom Collyer 2009-20.


  1. Very enjoyable! Particularly liked the second one - the geometry and signpost clues work together very nicely. I agree that it works well as a standalone type.

    By the way, it's great to see you posting here again. I look forward to many more excellent puzzles.

  2. Glad you enjoyed these Freddie. I suppose one worry is that the puzzles might end up a bit same-y if you keep the geometry the same, but there are no shortage of irregular guess out there. I suspect it might also be desirable to have some given digits as well. I’d be interested to see what other authors make of this type.

  3. I liked the puzzles, but for me, this is essentially just a Killer with some overlapping clues. There are some possible new deductions by this, but I liked the original idea of finding the regions. If I dont have to please the Sudoku police of course.
    I'm really glad you're posting puzzles again and I hope you find a spot with which you are more comfortable. I guess there are always enough people who appreciate nice puzzles, if you don't want to have anything to do with bigger projects or organisations (or some specific communities).

    1. Hmm, so I think the construct your own regions version is possibly limited with what you can do - basically it feels like you need to work out the regions from the outside and work your way in. I think the most impressive thing is constructing a puzzle that solves at all, but I'm not sure I'd like to solve more than 5-10 more.

      When it comes to sudoku variations I do seem myself more as a gardener rather than an exploratory botanist. I prefer to carefully select and cultivate particular ideas and themes which are pleasing to me, rather than dedicate myself to weird and wonderful novelties. Of course the gardener's job becomes far less interesting without the explorers providing a few new novelties here and there, but it is also not impossible for the gardener to do a bit of exploring every now and again too.

      So yes, I think this idea pleased me as it just seemed a bit nicer than jigsaw killer. Obviously there are big similarities, but then again you can say the same about the consecutive pairs vs. consecutive constraint as well - again I feel that the consecutive pairs constraint just feels that little bit nicer.


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