The New Sudoku Players' Forum

[Adley]

I 'm pretty new to this and have been breezing through the Diabolical Puzzles until this one. I'm not just looking for an answer, but an explanation. Please help me to move on with my life:
The original puzzle looked like this:

Code: Select all

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


I have made it to this stage:

Code: Select all

9        4        18 | 2       5       6 | 138     138     7 |
16      5         3  | 8       4       7 |  9        16      2 |
7        2        68 | 9      13     13 |  4        68      5 |
-------------------------------------------------------------
5        7        16 |146   1368  48| 2           9       136|
1368  1368     2 | 7        9       5| 13        134   1346|
136     9         4 | 16      2      13| 7           5         8 |
--------------------------------------------------------------
2       138      9  | 146   168   48| 5          7         13|
1348   138     7  |  5      18     2 | 6        1348      9 |
1468   168     5  |  3      7      9  | 18        2         14|
--------------------------------------------------------------



Thanks so much to all you more experienced puzzlers.

[tarek]

hi there Adley,

there are several box-line interaction (locked candidates) eliminations possible here (ex: Column 9 & Box 6).

If these were tough to spot, the I'm afraid to say that the path is full of thorns (doubles, forcing chains). It is a true diabolical.

Tarek

[Crazy Girl]

Code: Select all

9      4      18  | 2      5      6   | 138    138    7    |
16     5      3   | 8      4      7   | 9      16     2    |
7      2      68  | 9      13     13  | 4      68     5    |
------------------+-------------------+--------------------|
5      7      16  | 146    1368   48  | 2      9      136  |
1368   1368   2   | 7      9      5   | 13     134    1346 |
136    9      4   | 16     2      13  | 7      5      8    |
------------------+-------------------+--------------------|
2      138     9  | 146    168    48  | 5      7      13   |
1348   138     7  | 5      18     2   | 6      1348   9    |
1468   168     5  | 3      7      9   | 18     2      14   |
------------------+-------------------+--------------------|


Does a 'Diabolical' puzzle allow you to use chains to solve, or can it be solved with more standard/basic techniques (Naked/Hidden Pairs/Triple, X-Wing or Swordfish), as this one seems to need a chain to solve it, i think

[Adley]

Hi Tarek, I'm afraid to say I do not know what box line interaction elimations are. Can you elaberate?

And Crazy Girl, thanks for making my posting look so nice. I would like to learn how to do that.
As far as solving limitation, there are none. I would prefer to use logic rather than gueesing, if posssible.
So I can use chains, but alas I do not know what a chain is.

Any further help or insight is appreciated.

adley

[Crazy Girl]

Go here or here to understand the terms we use in this forum,

If you want to make your candidate grid more readable to other users, copy it into Word (or equivalent) and select Courier as the Font, then line everything up, copy it to here, and put code tags on it, and hey presto...

If you want to see what other people have done click "Quote" from the top of anyone's post to see how they did it.

To understand more about chains, Jeff has done a good job of explaining them in the Advanced Solving Techniques thread, this will give you more of an understanding of what they are, so when someone quotes one, you won't be completely out of your depth

[tarek]

Hi Tarek, I'm afraid to say I do not know what box line interaction elimations are. Can you elaberate?

Crazy Girl provided some links for u just above. I suggest to try the hard/fiendish puzzles prior to moving to the more advanced ones.

[tarek]

Does a 'Diabolical' puzzle allow you to use chains to solve, or can it be solved with more standard/basic techniques (Naked/Hidden Pairs/Triple, X-Wing or Swordfish), as this one seems to need a chain to solve it, i think

Most Diabolical/Superior puzzles seem to involve (Triples/Swordfishes) as the toughest techniques needed.

Quads/XY wing probably would be the next level (Still Called diabolical )

several puzzles in the past year (especially in the DT), posted as diabolical required Forcing chains to crack

[Adley]

Thanks tarek.
I have followed Carzy Girls suggestion of reading Jeff's posting on Forcing Chains. It's actually quite exciting. So much wonderful thought.
The only advanced technique I've used so far is the XY Wing. I have not used Swordfish, forcing Chains, etc. and not sure I know how.
I hope if I keep reading I will have a better sense.
It's definitely on the edge of where my mind can go.
Fun though.

Wish me luck.