Help please - I'm stuck

Post the puzzle or solving technique that's causing you trouble and someone will help

Help please - I'm stuck

Postby Tapestry » Sat Sep 06, 2008 11:08 am

Sorry my format is such a mess - not sure how to do it so that it lines up.

Here's the original puzzle:

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

Here's how far I've gotten:

+----------------------------------------+
| 6 3 18 | 57 2 57 | 4 189 89 |
| 2 7 4 | 13 9 8 | 13 6 5 |
| 5 9 18 | 34 14 6 | 38 7 2 |
|-------+-------+----------------------|
| 3 5 679 | 127 8 17 | 269 49 46 |
| 8 1 2 | 46 46 9 | 5 3 7 |
| 49 46 679 | 27 5 3 | 2689 89 1 |
|-------+-------+-----------------------|
| 7 8 56 | 9 136 2 | 16 145 346 |
| 1 2 569 | 8 36 4 | 7 59 369 |
| 49 46 3 | 156 7 15 | 1689 2 689 |
+---------------------------------------+

Thanks
Tapestry
 
Posts: 8
Joined: 15 April 2008

Postby tarek » Sat Sep 06, 2008 11:27 am

Tapestry,

The next move according to the pencilmarks IMO is a Swordfish ........

2 links for reading:
Ultimate Fish Guide
arcilla's thread

tarek
User avatar
tarek
 
Posts: 2631
Joined: 05 January 2006

Postby Glyn » Sat Sep 06, 2008 11:33 am

Tapestry

Firstly When you paste the puzzle into the editor box, if you select the grid and select the Code button it will add the appropriate formatting commands.



Now to the puzzle which has a Swordfish for digit 1. The three candidates you need for rows 2, 4 and 9 are restricted to columns 4, 6 and 7. When you solve the rows these columns will automatically be satisfied. The 1 in r7c7 is redundant so you can eliminate it. It's singles from here.

I've marked the Swordfish with X the eliminated candidate with -.

Code: Select all
.---------------.---------------.----------------.
| 6    3    18  | 57   2    57  | 4     189  89  |
| 2    7    4   | 1X3  9    8   | 1X3   6    5   |
| 5    9    18  | 34   14   6   | 38    7    2   |
:---------------+---------------+----------------:
| 3    5    679 | 1X27 8    1X7 | 269   49   46  |
| 8    1    2   | 46   46   9   | 5     3    7   |
| 49   46   679 | 27   5    3   | 2689  89   1   |
:---------------+---------------+----------------:
| 7    8    56  | 9    136  2   | -16   145  346 |
| 1    2    569 | 8    36   4   | 7     59   369 |
| 49   46   3   | 1X56 7    1X5 | 1X689 2    689 |
'---------------'---------------'----------------'
Glyn
 
Posts: 357
Joined: 26 April 2007

Postby Steve R » Sat Sep 06, 2008 12:28 pm

If, like me, you find conjugates easier to spot than swordfish, you can make the same elimination using the conjugates for 1 in row 2 and column 5:

Code: Select all
.---------------.---------------.-----------------.
| 6    3    18  |  57   2    57 |  4     189  89  |
| 2    7    4   | *13   9    8  | *13    6    5   |
| 5    9    18  |  34  †14   6  |  38    7    2   |
:---------------+---------------+-----------------:
| 3    5    679 |  127  8    17 |  269   49   46  |
| 8    1    2   |  46   46   9  |  5     3    7   |
| 49   46   679 |  27   5    3  |  2689  89   1   |
:---------------+---------------+-----------------:
| 7    8    56  |  9   †136  2  | -16    145  346 |
| 1    2    569 |  8    36   4  |  7     59   369 |
| 49   46   3   |  156  7    15 |  1689  2    689 |
'---------------'---------------'-----------------'

Steve
Steve R
 
Posts: 74
Joined: 03 April 2006

Postby tarek » Sat Sep 06, 2008 12:36 pm

Steve R wrote:If, like me, you find conjugates easier to spot than swordfish, you can make the same elimination using the conjugates for 1 in row 2 and column 5
This happens because a 2*2*2 swordfish exists, a colouring equivalent would not be there in the absence of that vaiety.

tarek
User avatar
tarek
 
Posts: 2631
Joined: 05 January 2006

Thanks...

Postby Tapestry » Sat Sep 06, 2008 1:01 pm

to all for their help!
Tapestry
 
Posts: 8
Joined: 15 April 2008


Return to Help with puzzles and solving techniques