View Full Version : Sudoku puzzle

vindaloo

24th Aug 2005, 09:44

Can anyone help with this Sudoku puzzle?

http://www.nappyevents.co.uk/sudoku.gif

I know what the completed puzzle looks like but can't see what the next step is. The puzzle comes under the category of 'fiendish'.

Thanks,

Vindaloo

The next one I can find is a value of 4 in box E4 (pairs test rule)

ie row 5 is 3_94172_6

Which then gives 8 for box C4 etc

Carry on........

vindaloo

24th Aug 2005, 10:54

Thanks CDH, you're a star :ok:

What I'd done was left a '4' pencilled in E8, which invalidated the pairs test rule for this row.

Back to work now!

Vindaloo

Link a brother to the pairs test rule web site? I am of the fill in every possibility school.

Pairs Test.

Basically, you can eliminate numbers if two squares have two identical pairs of numbers. For example, if a row has 3-7 and 3-7 then all other 3s and 7s in that row can be eliminated. Same goes for the box and column.

Did you follow that?

Reading it again almost didn't make sense...:hmm:

Back to Vindaloos example

because row 5 box 2 can only possibly be a 5 or an 8 & the same applies to box 8 then box 4 can only be a 4 & not a 5 or an 8.

Simple...but only when you can see it ;)

N380UA

24th Aug 2005, 13:01

Does the answer look like this?

425 361 879

816 279 354

937 854 621

264 398 517

359 417 286

178 562 493

693 125 748

782 946 135

541 783 962

patdavies

24th Aug 2005, 14:00

Back to Vindaloos example

because row 5 box 2 can only possibly be a 5 or an 8 & the same applies to box 8 then box 4 can only be a 4 & not a 5 or an 8.

Simple...but only when you can see it

May be I was looking at it too long, but I can't see how you can eliminate 4 from box 8???

4PON4PIN

24th Aug 2005, 14:31

Patdavis

Bottom right square: H7 = 4 or 6, H8= 3 or 4.

Since a 4 must appear in centre column of that block, then H5 is restricted to 5/8 instead of 4/5/8.

:ok:

N380UA

24th Aug 2005, 14:38

Seems like ya'll need some instruction on this game.

Place the number 1 through 9 in every row and column and within every box in such way that that every number only appears once across the rows and column and within the boxes. No math is needed, only logic.

The example vindaloo has posted above seems fairly easy. The puzzles below appear a bit more difficult. Those puzzles take between 10 and 30 minutes depending on experience and skills.

http://www.wiley-vch.de/dummies/sudoku/

http://www.sudoku.com/

vindaloo

24th Aug 2005, 15:44

Does the answer look like this?

425 361 879

816 279 354

937 854 621

264 398 517

359 417 286

178 562 493

693 125 748

782 946 135

541 783 962

That's correct, except the top row should read 425 631 879 (i.e. reverse the 6 & 3 which I'm sure was only a typo on your part).

The example vindaloo has posted above seems fairly easy.

Yes, it looks easy because I'd already filled half of it in and then got stuck on a mistake which needed a fresh pair of eyes. Trust me, it wasn't an easy one to start with ;)

For anyone who enjoys these sort of puzzles, here's a good site with several different styles of puzzle (although they all require the same techniques to solve them). You can solve them online which makes it a lot easier, but be prepared to lose a lot of free time!

http://www.puzzle.jp/en/

Vindaloo

N380UA

25th Aug 2005, 08:02

Cheers Vindaloo

It was a typo actually. I didn’t know you'd already finished half of it that’s why it seemed easy as there were a lot of answers given already.