The New Sudoku Players' Forum

[sam]

Hi,
I am new to this, but like everyone else, totally addicted!!! Much to the detriment of EVERYTHING else for the last week!!!
I bought the Daily Telegraph Suduko book as I was spending too much money on papers and quickly worked through some of the hard ones. I did a Diabolical Suduko yesterday in an hour, but the one I tried today had me stumped for hours. I finally gave up logic and guessed Row 6 Column 8 (X) was an 8 (option was 8 or 2) and after that I solved it very quickly.

What I would like to know is, is there a logical way I could have solved it?

214 3-- -9-
--3 4-- 8--
68- --2 -34
--- -26 --7
--6 74- 5X-
472 85- -6-
32- --- --9
-48 --7 25-
-6- 2-4 -18

Really look forward to your answers! Please dont get too technical, I find it hard to follow some of the explanations I have looked at!!!

Thanks!
Sam

[Animator]

The problem with the Daily Telegraph is that some puzzles requires trial and error...

First of all, is the X in your post a typo or not, as in, is it a clue or not?

If it isn't a clue then you need the Nishio technique to solve them... and that one is really close to trial and error...

[sam]

The X is where I guessed between an 8 and another number. Ah so is that why everyone on here prefers the times? More logical?



I just didnt want to get in the habit of having to guess rather than working it out, so your reply has made me a bit happier!

I am intrigued though, what is this nishio technique you speak of?!

Thanks!
Sam

[Animator]

Yes, that basiclly is the reason why people prefer the Pappocom puzzules (which are the ones published in the Times). They guarntee a unique solution which you can reach by logic.

The Nishio technique is trial and error, but limited to a single number.

As in, you fill in a number, and see if you can still place the number in the other boxes aswell.

For example, there is a Nishio in this puzzle in the number 7 (there is also one in the number 1, but that one is irrelevant).

See what happens when you try to fill in the number 7 in r7c3. (only look at the number 7 though). You will reach a dead end, this allows you to exclude it from r7c3.

When that is excluded you can find a pair of 4 and 7 on row 7. This allows you to fill in the number 6 and the number 3 in box 9.

[sam]

ok thanks! I will try the times ones!