All entries for Friday 04 June 2010

June 04, 2010

Friday Puzzles #55

Mission accomplished! Weekly numbering is now completely in order. Modulo the missing #7 and #17 that is. Still, there were a couple of weeks where I made bonus puzzles so I think that just about balances out the equation. I must add that I revisited the double-toroidal sudoku, but I have to say that with its current grid I lost a bit of interest.

Anyhow, a sudoku variant this week which I think I’m right in claiming has only ever been pulled off by yours truly – although please correct me if I’m wrong. In case you missed the original post the idea with 10’s sudoku is normal sudoku rules, except that every time a pair of adjacent cells had digits summing to 10, they are marked. Where there are no markings between adjacent cells, the conclusion is then that the relevant digits cannot sum to 10.

Prior to that post, I can’t find an example where 10’s sudoku had no such marked occurrences between pairs of digits, but it turns out with a bit of work that it’s perfectly possible. I’m sure a computer-y type would easily be able to write a program to churn out more of these without working up any sort of a sweat, but that’s not the way I roll. There’s plenty of potential with this variant to churn out some really fiendish challenges; this example is fairly plain sailing, but perhaps with a couple of surprises along the way. Enjoy!

UPDATE: My apologies to those who had a go at an earlier version of this puzzle, which had two solutions, and my thanks to Jack who pointed this apparently obvious blooper I managed to completely miss! My reputation for errors seems to be growing, but stick with me anyway – at the very least you won’t be bored!

#065 No Tens Sudoku – rated medium

All puzzles © Tom Collyer 2009-10


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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Latest comments

  • I like the appearance of the solution. :P Nice one. by Prasanna Seshadri on this entry
  • I think I've seen something vaguely similar in some of Palmer's puzzles as well. To be honest I've a… by on this entry
  • That's two puzzles in a row where I find something I had used before. I know, not plagiarism; just g… by Bram on this entry
  • Kota, that's not really true. I had made my puzzle before going to the WPC already. Also I don't hav… by Bram on this entry
  • About 20 minutes, after restarting from a mistaken conclusion. by Bryce Herdt on this entry

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