December 24, 2010

Friday Puzzles #84

Happy Christmas, dearest reader!

I nearly forgot to put out a post – just like the good old days – but luckily enough there was something lurking at the bottom of the pile in my “unpublished” folder.

And with good reason too.

Christmas is an occasion the newspapers like to fill with bumper sized crosswords, and extra hard sudoku puzzles, and other puzzling novelties given that we have all this spare time on our hands. The thing with this puzzle is it’s much harder than that. Enjoy!

#110 Sudoku – rated hard

All puzzles © Tom Collyer 2009-10

- 4 comments by 1 or more people Not publicly viewable

  1. Ours brun

    I wouldn’t call it a very hard sudoku by itself, but it is certainly much harder than most of those published in newspapers, indeed.
    By the way, it is nice to look at and was nice to solve.

    27 Dec 2010, 01:13

  2. Thanks for the comments – I generally find it quite difficult to come up with difficult puzzles entirely by hand – and I think I used scanraid to tweak this puzzle a little bit to retain the spirals! Most of the toughest sudoku are those that are found by some trawling computer generator. I don’t think I have seen many hand crafted much-harder-than-newspaper puzzles outside of round 10 of the WSC this year. Perhaps if Thomas is reading he can shed some light on to how he went about putting those puzzles together?

    28 Dec 2010, 17:18

  3. TheSubro

    Nice puzzle, in looks and in solving. I never know how to rate a Sudoku. The only advanced steps needed here were a few XY chains (and possibly a Y-Wing thing). Not exactly diabolical, but much more complez than most US newspapers would offer. My experience with London papers makes me think that a few are as complex as this one on a weekly basis


    29 Dec 2010, 05:03

  4. Ours brun

    Indeed, you could use XY-Wings or XY-Chains but I personnally used unicity (basic unique rectangle). Very easy to spot, and it killed the puzzle – that’s why I didn’t find it that difficult. There are specialists of high difficulty who are able to craft harder sudokus (really harder) by hand, but I can’t tell you the way they do so.
    In France, a few monthly publications offer harder puzzles than this one but of course, all are computer-generated.


    29 Dec 2010, 14:45

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Welcome to the blog of current UKPA sudoku champion, two-time Times national sudoku champion and general logic puzzle fan Tom Collyer.

Home of the original Friday Puzzles, each Friday I publish a 100% original and handmade logic puzzle, inspired by the world-famous Nikoli company.

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