about 2 months ago - No comments
Jigsaw 6×6 puzzle 2Jigsaw 6×6 puzzle 1I just made some Jigsaw Sudoku puzzles for a book and had a couple spare which I thought I’d post here. Just place A to F once each into every row, column and bold-lined jigsaw shape.
about 1 year ago - No comments
Sudoku 6×6 puzzleJigsaw 6×6 puzzle
I had a couple of 6×6 Sudoku puzzles left over when making issue 58 of Sudoku Pro magazine, so I thought I’d post them here.
Just place 1-6 into each row, column and bold-lined area.
about 1 year ago - No comments
Sudoku 16×16 puzzle
And to complement the Killer Sudoku I posted a moment ago, here’s a 16×16 puzzle for those who like these. Just place 1 to 9 and A to G in each row, column and 4×4 box. Only “scan and place” logic is needed for this, I promise!
about 1 year ago - No comments
Samurai 8X puzzle
When I was making Sudoku Xtra 10 I wanted to put in a really big Samurai Sudoku puzzle. In the end because I had a square page area available beneath the instructions I went with a 13-grid one (just as a one-off to see what sort of reaction it got!) but I had More >
about 1 year ago - No comments
Killer Plus Minus Samurai puzzle
If you’re a Sudoku Xtra reader you’ll have seen these in their regular 9×9 form in both issues 5 and 6, but this is the first time I’ve made a Samurai one, and the first time I’ve posted one here I think.
This is essentially a regular Killer Sudoku puzzle, except that More >
about 1 year ago - No comments
Killer Sudoku Pro 6×6 Samurai puzzle
It’s been quiet here recently – much of my effort has been going on my UK General Election site, How To Vote, although Sudoku Xtra 6 was out on Saturday too. Anyway, there are still 10 days to go to the election but after that I’ll get some time back!
However I thought I should More >
about 1 year ago - 1 comment
Samurai 3-grid Calcudoku 6×6 puzzle
I’ve been posting a few new varieties of Sudoku puzzle in the daily puzzle section of PuzzleMix (i.e. the subscription section, which costs less than £1 a month for well over 1,000 puzzles a year). These aren’t especially unusual variations, but I’ve done a few different mixes (e.g. Sudoku-X 12×12 and More >
about 1 year ago - 3 comments
Toroidal Killer Jigsaw Toroidal puzzle
A while back someone asked for some variant toroidal patterns on PuzzleMix, so I was just adding a couple of them to the daily puzzles section when it occurred to me that I could put up a few toroidal killer sudoku too, for a change. However I then realised that the More >
about 1 year ago - 1 comment
Samurai Star XXXXX puzzle
I haven’t posted a puzzle for a week (it’s been a busy week, mind!) so it’s time to make up for that, just in time for the weekend.
In this puzzle the aim is pretty simple: place 1 to 9 in each set of 9 squares starting and ending with a bold line, More >
about 1 year ago - 2 comments
I wrote quite a lot yesterday about whether you “needed” the X in some Sudoku-X puzzles. I promised that I’d follow up with the result of analysing a stack of Killer Sudoku-X puzzles, and so here is that result.
I picked 64 Killer Sudoku-X puzzles (52 for the daily puzzlemix section plus 12 for the weekly More >
about 2 years ago
Yum Yum Fun!
*****
SPOILER!
*****
I am not sure what nasty hidden set you were referring to. At the start of the puzzle I worked on the center box and very lower box. Then I did the conga line of consecutives in the middle right row.
Once you do this and apply the samurai flower rule diligently, the puzzle breaks down rather nicely. I think there were a few times I had triplets with a pair of consecutive numbers with no bars in the row/column … which meant the non-consecutive number had to be in the middle square.
I enjoyed this one. Thanks.
about 2 years ago
Ah, now that’s a good point – I’d overlooked that! I ran my sudoku analysis software on it but it doesn’t look at multiple groupings of consecutive markers in the same region, considering only any chosen pair at once. If you don’t look at region cooccurrences then you need a hidden quad towards the end, but of course any human solver would make the more intuitive deduction instead.
You can see a similar issue in Futoshiki if a computer solver considers only pairs (the obvious way to implement). If a>b<c in a single row/column then in (say) a 5×5 grid clearly b cannot be 4, but if you consider only pairs then the only deduction the computer will make is that b is not 5 (without any other information at any rate). Whilst it’s not hard to make a machine more intelligent (it can easily run an exhaustive search) the problem soon becomes that you make puzzles that are far too hard – so I’ve always thought it better to err on the side of too easy than too hard!
Of course, if you have the time and inclination then the best solution of all is to make explicit implementations of all the things you find yourself doing as a human solver – then you can be sure it’s fair and tricky! 
about 2 years ago
This was a great puzzle – just the right degree of difficulty for me – challenging but manageable. As you probably know by now, I don’t do the sudoku solving jargon (I’ve never got to grips with it, though I’m sure I use some of the strategies without realising it). Just to say that once started I managed this without too much difficulty. Like Spittledung I started with the lower centre box, and then looked at the very long line of consecutive numbers in the middle, and with some thought the puzzle seemed to fall into place. It took me about an hour to complete.
Now to get back to the 12 x 12 one – I’m not getting anywhere fast with that. I may be asking for a few hints soon!