The New Sudoku Players' Forum

by **Akiyama** » Fri May 13, 2005 10:59 pm

I read the Guardian. They started publishing sudoku this week (Monday 9th May) so I gave it a go.

They claim their hand-made sudoku are superior to computer generated ones. Has anyone noticed any difference? I've never attempted computer generated ones.

The Guardian's sudoku increase in difficulty throughout the week, so Monday's is the easiest and Friday's is the hardest. I could do Tuesday's and Wednesday's no problem but got into a right mess with Monday's, Thursday's and Friday's.

Has anyone here managed to do Friday's? That's Friday 13th May. Was it particularly difficult? Did it require arcane solving techniques? I carpet-bombed it but still couldn't solve it.

by **Animator** » Sat May 14, 2005 10:45 am

If you really want an answer then it would be easier if you post the puzzle... (or an url to it, if they are published on the Guardian's site too...)

by **Guest** » Sat May 14, 2005 8:08 pm

I was delighted to see the Guardian join the fray, as this is my normal paper of choice, and I've been having to buy other papers to get my Sudoku fix! I also wondered about their 'moral high ground' stance of 'hand made' Sudoku - I think this is just marketing ploy, but maybe I'm not experienced enough to tell the difference. That said, I have noticed that the ones in the Guardian often have a nice symmetry about them.

With respect to Friday's puzzle, as there was a Sudoku on each page, which one were you referring to?

At the risk of covering too many topics in one thread - I'm wondering if the correct name is one word (Sudoku as on this site and the Guardian) or two (Su Doku - as in the Times).

by **Ward** » Sun May 15, 2005 4:43 pm

Friday's has me beat too.

Code: Select all: .8.|.1.|.6. ..1|..5|..8 7..|...|1.. ----------- ..3|...|..4 .2.|.6..7. 5..|...|3.. ----------- ..4|...|..1 1..|2..|5.. .6.|.7.|.2.

I have so far that Col 1 Row 7 has to be 2
Col 7 Row 4 and Col 9 Row 6 are 2 or 6 but don't know which
Col 7 Row 7 and Col 9 Row 8 are 6 or 7 but don't know which

I am hung up on the feeling that Col 4 Row 5 and Rol 6 Row 5 are the key to moving on, one of them is obviously 3 but I'm blown if I know which one or what else they could be.[/code]

by **Animator** » Sun May 15, 2005 5:17 pm

Ok, here is a hint:

Look at row 5, there are two celss that have only 8 and 9 as candidates. If you reliase that you can remove 8 and 9 as candidates from the others cells (cell r5c1 and r5c9 to be precise, those are the intresting ones)

by **Ward** » Sun May 15, 2005 5:24 pm

8 or 9 tip is what I needed, thank you... got now that Row 5 Col 1 has to be 4, Col 9 has to be 5. Had written in the top left of every box each and every possible number it could be, and looked over them time and time again, very annoyed with myself for mssing your 8/9 on Row 5! Will continue....

by **ArchieB** » Mon May 23, 2005 10:57 pm

I've been doing the Guardian Sudoku puzzles since the middle of last week (18th May) and am gradually speeding up.
For today's (Monday 23rd may) "easy" puzzle no.013 I get two solutions:

123 487 956
649 532 871
875 619 432

298 761 543
314 258 697
567 943 218

786 194 325
932 875 164
451 326 789

and

123 487 956
649 532 871
857 619 342

298 741 563
317 258 498
564 963 217

786 194 325
932 875 146
451 326 789

Is this double solution regarded as OK?
Should I email the guardian letters page and complain?
Or has somebody beaten me to it?

by **simes** » Tue May 24, 2005 7:00 am

The second solution isn't. There are two 7s in column 3, two 5s in column 2, two 3s in column 7, two 4s in column 8, two 6s in column 9. Oh, and some of the rows are wrong too!

by **ArchieB** » Tue May 24, 2005 5:08 pm

Damn me, so there are
How did I miss that?
Sorry!

by **Guest** » Sat May 28, 2005 12:15 am

I have found that the Guardian Sudokus are all valid puzzles, solvable by using logic only - no trial-and-error guesswork is required (unlike the "Diabolical" puzzles in the Telegraph which appear on Fridays)

Perserverance and practice pays off. Sometimes I have sepnt ages looking at a puzzle, only to suddenly see where a particular number must go, and then I'm on a roll.

The easy Gaurdian puzzles take me about 15 minutes, whereas the hardest ones take aout 90 minutes (they did suggest that Friday's puzles may take until Saturday to complete!)

by **ArchieB** » Wed Jul 13, 2005 11:46 pm

I've been doing the Guardian puzzles regularly for several weeks now and although I've occasionally made a mistake and had to re-start I've always got to the solution by simple logic - even the dificult ones. Monday's Scottish Daily Record prints six puzzles, which I've found to be much the same as the Guardian ones.

Should I be seeking out something harder?
What do you recommend?

by **scrose** » Thu Jul 14, 2005 1:52 pm

ArchieB wrote:Should I be seeking out something harder? What do you recommend?

If you are looking for more difficult sudoku puzzles, you could try puzzles with overlapping grids, such as the Samurai Sudoku found in The Times. This website has a large collection of overlapping grids, starting at puzzle #70.

If you are looking for puzzles that require advanced solving techniques (such as x-wing, swordfish, colouring, etc.) you could try the "very hard" puzzles generated by the Pappocom software (x-wings only). Or you could download the advanced puzzle packs provided by angusj.

by **PaulIQ164** » Sat Jul 16, 2005 6:24 pm

By the by, there was a bit of a thing a while ago about The Guardian's puzzles having "almost imperceptible witticisms" built into them (because they're handmade, of course, not generated by evil computers!) - "312875946" apparently being an example of this. Was this all just a huge joke, or is there really such thing as a witty permutation of the numbers 1 to 9?

by **ArchieB** » Wed Aug 10, 2005 1:22 pm

Guardian Notes & Queries today printed a comment from one Tom Barry who claimed that Guardian puzzle 053 has at least 5 different solutions".

Having printed off a copy of this puzzle from the Guardian Unlimited website, and solved it to a single answer in about 20 minutes, I have sent a response to N&Q refuting Tom Barry's claim. Unfortunately, GU does not publish solutions, so would someone else like to try the puzzle and confirm the solution.

Ta. Puzzle & my solution follow

. . . | 8 . . | 5 . .
. . 4 | . . . | . 6 .
. 1 . |. 9 . | . . 7
-------+-------+------
6 . . | 1 . . | . 8 .
. . 7 | . . . | 3 . .
. 2 . | . . 5 | . . 4
-------+-------+------
5 . . | . 7 . | . 1 .
. 3 . | . . . | 6 . .
. . 9 | . . 4 | . . .

My solution:

976 | 841 | 523
854 | 327 | 961
213 | 596 | 847
-------+-------+------
645 | 139 | 782
197 | 482 | 356
328 | 765 | 194
-------+-------+------
562 | 973 | 418
431 | 258 | 679
789 | 614 | 235

by **simes** » Wed Aug 10, 2005 2:33 pm

According to my solver, it has a single solution.

Simes