much harder

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Postby Guest » Thu May 26, 2005 9:55 pm

I have only been doing Su Doku for 3 days, and have gone from easy mild to diffiuclt , have done 4 'difficult' puzzles. Do the 'fiendish' puzzles require any different techniques, do people find them a lot harder? thanks
Posts: 312
Joined: 25 November 2005

Postby Arnie » Fri May 27, 2005 5:49 am

Hi and welcome !

I believe that as you start tackling more difficult puzzles, you need to learn new tips and tactics to solve them. I am not one of the real "experts" in this forum but on a good day with a fair wind can solve these and am currently endeavoring to open the secrets of "very hards" . I couldn't do this without the aid and assistance of this fourm.

Tackling "fiendish" puzzles can be a brute - feel free to share the puzzles here so people more experienced that I can point you in the right direction. this forum is excellent for seeking help when you get stuck and become convinced that the particular puzzle you have in front of you is impossible to solve !!

Personally, I find the fiendish puzzles a "step up " from difficult. Whilst the start of these puzzles is usually benign iwth a few clues or pencil marks easily being slotted in, what I find is there comes a defining moment in these puzzles. this is where I appear to get stuck - and usually this is because there are only 1 or 2 possibles moves that can be taken from this point to move the puzzle on.

Things to look out for at such moments are:

- recheck you have not missed simple solutions

- "pairs" in a row/column/box

- subsets - where you can identify,say, 3 cells that can only have 3 numbers in - hence the other 6 numbers must occupy the other cells

- identify those numbers in each box where you havenot got pencilmarks or "big numbers". you can sometimes eliminate numbers by seeing if these "unused" numbers can be eliminated from certain cells

- have a break and come back - you can be amazed what a fresh mind can do

I'm sure there are other tips for solving these beasts but I hope this helps and you get some of the enjoyment I've had in doing these.

Good luck.....!
Posts: 49
Joined: 19 May 2005

Postby Guest » Fri May 27, 2005 7:12 pm

Just to elaborate on what Arnie said, re pairs or pairings of numbers. If in a particular column or row, there are only two cells that can possibly contain the same two numbers, then those two cells definitely contain those two numbers. Given this fact, those two numbers may then be rubbed out of all the other cells in the row or column. If both cells are in the same 9x9 box, those two numbers can be eliminated from all other cells within that box.
Posts: 312
Joined: 25 November 2005

Postby Guest » Fri May 27, 2005 7:37 pm

When you look down your pencil marks in a row of nine cells, if you have, say, possible 3s restricted to one 9x9 box, you can then eliminate the 3s from the other cells in that box.

If, in a 9x9 box, you have, say, 3s as possibilities in only one row or column, you can eliminate any other 3s in that row or column outside of that box.
Posts: 312
Joined: 25 November 2005

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