The New Sudoku Players' Forum

[jaymed]

Greetings all. I have just started playing Sudoku and am enjoying it. Most of my solving strategies (thus far) has been using squeezing or cross hatching. However, I have some puzzles that I am stuck on and these techniques aren't helping me get any further. If anyone recalls being a beginner like myself, what is the next technique I need to learn to improve my solving skills? (an explaination of the technique would also be appreciated!)

[Pat]

I have just started playing Sudoku and am enjoying it.

Most of my solving strategies (thus far) has been using squeezing or cross hatching.

However, I have some puzzles that I am stuck on and these techniques aren't helping me get any further.

If anyone recalls being a beginner like myself,
what is the next technique I need to learn to improve my solving skills?
(an explaination of the technique would also be appreciated!)

hi jaymed

may i suggest you post just one of those puzzles where you're stuck?

so that we know better in which direction to point you---

[jaymed]

Thanks for the response Pat. I'll be more than happy to post my puzzle...there are a few though Is there a format I should use so it will be easier to read? If so, please provide a link and I'll post it!

[ab]

Hi Jaymed
there's a pretty comprehensive list of solving techniques here:
http://forum.enjoysudoku.com/viewtopic.php?p=21804#p21804
you should probably start with locked candidates and hidden and naked pairs. That should help you solve most newspaper puzzles. But there are a lot harder sudoku out there, even in some newspapers, like the Times in the uk, the London paper and the Metro. To solve these you'll need to learn about x-wings and hidden and naked triples.

If you take Pat's advice and decide to post a puzzle you're stuck on, post it here:
http://forum.enjoysudoku.com/viewforum.php?f=17
You might want to start by looking at some of the puzzles posted there and some of the replies

[Pat]

just use

[code]

puzzle
goes
here
[/code]

[jaymed]

Code: Select all

*46 *8* *12
513 672 984
2*8 14* 63*
**5 82* 3*9
489 *6* *21
**2 *9* 8**
*** *16 2*8
621 758 493
8**23* 1**


Thanks Pat, lets hope I did this right.

AB, thanks for the links and the advice. It sounds like I should focus on locked candidates and hidden/naked pairs. I read a bit on some of the links but I think I'll learn better if I post a puzzle and have someone explain the theories because I've been racking my brain on them already for a bit

[Pat]

Code: Select all

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



thanks -- too tough for me -- probably much too tough for a beginner

[Pat]

what i can do with this puzzle (for a beginner)
is to point out -- in case you haven't seen it --

• in box 4, the 3 must be in row 6
  -- exclude 3 elsewhere in that row
  
• in column 3, the 7 must be in box 7
  -- exclude 7 elsewhere in that box

[Pat]

too clarify my earlier comment about this being Too Tough --
SuDoku Explainer can show you a solution-path using X-wing + turbot,
and you then still need an xy-wing.

[Glyn]

jaymed Welcome to the forum. Yes that code works perfectly for me.

Here are the pencil marks based on the cells you have solved.

Code: Select all

.------------------.------------------.------------------.
| 79    4     6    | 359   8     359  | 57    1     2    |
| 5     1     3    | 6     7     2    | 9     8     4    |
| 2     79    8    | 1     4     59   | 6     3     57   |
:------------------+------------------+------------------:
| 17    67    5    | 8     2     147  | 3     467   9    |
| 4     8     9    | 35    6     357  | 57    2     1    |
| 137   367   2    | 345   9     13457| 8     4567  567  |
:------------------+------------------+------------------:
| 379   3579  47   | 49    1     6    | 2     57    8    |
| 6     2     1    | 7     5     8    | 4     9     3    |
| 8     579   47   | 2     3     49   | 1     567   567  |
'------------------'------------------'------------------'

This is quite an ambitious one to try when moving from locked candidates as it requires too many new techniques in one leap.

For this one X-wings, XY-wings, Turbot Fish might be useful to read about in that order. There are several routes through from here depending on the combination of the choice of these techniques. The ones I've tried all led to the determination of r5c7 as being key. The Sudoku Explainer rating, which you may see mentioned elsewhere, is 6.6.

Thanks to me being too verbose Pat has said most of this already.

[jaymed]

Thanks for the replies...I took that puzzle out of the Boston Herald so I'm suprised it's so hard. I'll keep it in my archives and take a look at it as I improve my solving skills; no point in running before I can walk. Lets see if I can learn based on this puzzle I got out of the USA Today. It's mostly complete and I have the answer to the puzzle but I can't figure out WHY the numbers are going where they should go.

Code: Select all

 
**7 265 934
523 849 *7*
4** 173 *2*
2*4 531 7**
*7* 492 **3
3*1 786 **2
74* 318 ***
*** 6*4 387
638 9*7 ***


Another question, I believe Glyn posted pencil marks for my puzzle. What is that and how can I use them to help solve puzzles??

[Pat]

USA Today

Code: Select all

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



this one is all "hidden singles"

place a 9 in column 1

[jaymed]

Thanks Pat...now that you gave me that hint I don't know how I couldn't see it earlier