All entries for April 2010

April 25, 2010

Friday Puzzles #42

Yes not a Friday. I don’t care! This is fortress sudoku. Notice the shaded “fortress”. The numbers that go in these shaded cells must be bigger numbers than those in unshaded cells immediately adjacent to them. Enjoy!

#052 Fortress Sudoku – rated medium

All puzzles © Tom Collyer 2009-10

April 23, 2010

Friday Puzzles #41

So sudoku fans, with less than a week to go until the world sudoku championships, I’ve decided to spoil you rotten.

Here are three puzzles that will 100% definitely appear in the championships in a form quite similar to what I’m giving you. Additionally, I’m going to try and publish a puzzle a day until next Wednesday, each one a variant definitely appearing in Philly.

This week, I give you: Integer Division Sudoku, Surplus Sudoku and Deficit Sudoku.


#049 Integer Division Sudoku – rated easy

#050 Surplus Sudoku – rated easy

#051 Deficit Sudoku – rated easy

All puzzles © Tom Collyer 2009-10

April 16, 2010

Friday Puzzles #40

So my sudoku variation bandwagon keeps on a-rollin’. This week, non-consecutive sudoku. This is basically sudoku as you know and love it, but with the added constraint that no two adjacent cells can contain consecutive cells. As with last week, this is my first attempt at constructing one of these variants, and whilst decent enough for me to put my name to it on this blog, it doesn’t quite (in my opinion) reach the standards of a perfectionist. Enjoy!

#048 Non-consecutive Sudoku – rated medium

All puzzles © Tom Collyer 2009-10

April 10, 2010

What Is And What Should Never Be

Yup – the Led Zeppelin titling is well and truly on.

Anyhow, this is just a note to my avid and loyal readership who are no doubt bemused by the fact that Warwick IT Services are doing all sorts of tinkering with their servers – meaning that the Friday puzzle image files are only sporadically appearing at this moment in time. There’s not a lot I can do about that I’m afraid, so you’ll just have to keep checking back later when hopefully the aforementioned tinkering has been completed.

On a completely random note, here are some utterances that can only very rarely have been voiced in the past:


That is all.

April 09, 2010

Friday puzzles #39

Another sudoku variant this week, this time “extra region”. This does what it says on the tin really, same sudoku rules with the added constraint of having 1-9 in the shaded regions as well. This hasn’t really come out as perfectly as I’d have liked in terms of the logic needed to solve this, but I suppose the consolation is that it’s not too difficult. Enjoy!

#047 Extra Region Sudoku – rated medium

All puzzles © Tom Collyer 2009-10

April 03, 2010

Friday Puzzles #38

A belated entry this week, as I have been travelling somewhat. There’s more travelling to look forward to at the end of the month too, with the world sudoku championships in Phiadelphia. As such, this week’s puzzle is a sudoku variant known as Arrow Sudoku. Standard sudoku rules apply, and additionally, the number that goes into a grey circle is precisely the sum of the numbers to be found on the corresponding arrow.

Do note that numbers can repeat on the arrows, and enjoy!

#046 Arrow Sudoku – rated hard

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.

How to play:
AkariFillominoHashiHeyawakeHitoriKakuroLITSMasyuNumberlinkNurikabeRipple EffectShikakuSlitherlinkSudokuSuraromuYajilin.


April 2010

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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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