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03 February 2011 @ 09:43 pm
Friday Puzzle #87 - Tournament Sudoku  
I don't write too many classic sudoku; in part because it's challenging to make them stand out from all the computer-generated sudoku out there and in part because there is simply no market that "pays" for classic sudoku because the random scatterings of digits from a PC are essentially free.

Still, I do enjoy exploring different classic sudoku themes, and making challenging puzzles that only require "simple" steps. Fortunately every year I write 7 puzzles for the Silicon Valley Puzzle Fest tournament (my previous years' puzzles can be found here, here, and here). This week's Friday Puzzle consists of the puzzles that were highlighted last weekend. This year I tried to make some slightly harder puzzles while still exploring interesting geometries and some unusual themes. I particularly like "Missing Digit?", but I think the solving paths of other puzzles like "Button" came out really well too.

The winner - James Wilson of San Francisco - averaged about 5 minutes on each of these puzzles including the final, so use that as your par time if you want to play along at home.

Rules: Place the digits 1 through 9 into the empty cells in the grid (a single digit per cell) so that each digit appears exactly once in each of the nine rows, nine columns, and nine outlined 3x3 regions.

Adult Round Puzzles:


Youth Puzzles:

(Anonymous) on February 4th, 2011 12:38 pm (UTC)
I win?
motris motris on February 4th, 2011 04:53 pm (UTC)
Nope. Anonymous commenters that provide no solving times are automatically disqualified.

To others: I would be glad to see what the times are for these puzzles from good international solvers. I expect 2-3 minute times from the world's best, but seeing which one(s) trip some solvers up is always interesting to me.
Fred Stalder Fred Stalder on February 4th, 2011 07:33 pm (UTC)
Ok, here are my solving times:

Button: 3'15
Window Frame: 2'52
Missing Digit?: 2'42 (without a missing digit lol )
Winners Podium: 4'02
Checkerboard: 1'23
Tunnel Vision: 1'40
Stripes: 2'20

figonometry figonometry on February 5th, 2011 03:03 am (UTC)
Well, I guess I've proved myself to not be a 'good international solver'. I only got two under two minutes, with the rest well over five.
figonometry figonometry on February 5th, 2011 03:27 pm (UTC)
Sorry, that should be "two under *three* minutes, with the rest well over five".
(Anonymous) on February 6th, 2011 09:52 pm (UTC)


The top lot should be taken with a pinch of salt since I wasn't using pencil-marks (I was solving in paint). The bottom lot didn't need pencil-marks, but are probably ~15 seconds slower than I'd be with pen and paper.

Teesside Snog Monster: swings jiggery_pokery on February 4th, 2011 05:44 pm (UTC)
I trust that US types know that Martha Stewart is looking to fill an audience with puzzle fans for a puzzle-themed episode of her show? Star guest pictured top left, and it ain't me.

Personally I can think of a few other potential guests of honour who'll be reading this that they should pay to travel to the taping with all the frills, but it's not my show. Unfortunately.
(Anonymous) on February 5th, 2011 10:32 am (UTC)
Yay - some artistic classics...

Buttons: 3.41 (but incorrect, so gave up )
Window Frame: 2.31
Missing Digit?: 5.55
Winner's Podium: 6.55
Checkerboard: 1.53
Tunnel Vision: 2.47
Stripes: 2:03

I liked how the givens are all 'used' - in most computer generated puzzles, givens are usually given in excess amounts.