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PoppaPoppa



Joined: 06 Nov 2005
Posts: 21
Location: Arkansas USA

PostPosted: Thu Dec 29, 2005 4:42 am    Post subject: Reply to Someone_Somewhere Reply with quote

sorry, Munich, I don't understand. I don't see a naked pair of 4 5 atr3c7 - there is also a possible 9 there, nicht wahr?
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someone_somewhere



Joined: 07 Aug 2005
Posts: 275
Location: Munich

PostPosted: Thu Dec 29, 2005 7:51 am    Post subject: Reply with quote

Hi Popa,

Same response as I have posted on the other thread:

Ok.
Let's take a deep look at the 6-th 3x3 block, with the corners: r4c7-r4c9-r6c9-r6c7.
Digit 7 is in r2c8. So it can't be in r7c8 and can't be in r9c8. So, it must be r7c7, r8c7 or r9c7 (it has to be one of the boxes of the 9-th 3x3 block).
This leaves us for digit 7 in the 6-th block only: r5c9 or r6c9.

Now let's concetrate on digit 4.
From 1-st 3x3 box we know that it has to be in r1c1 or r1c4. So it can't be in r1c9.
From 2-dt 3x3 box we know that it has to be in r2c4 or r2c5. So it can't be in r2c9.
4 is in r4c6.
So we have to have a 4 in column 9 and the only posibilities left are r5c9 or r6c9.
So 4 can't be in any other place of the 6-th 3x3 block.

Now we have our Hidden Pair 4, 7 in r5c9 and r6c9.

Hope this could help, if not I will try again.

see u,
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PoppaPoppa



Joined: 06 Nov 2005
Posts: 21
Location: Arkansas USA

PostPosted: Fri Dec 30, 2005 1:12 am    Post subject: Again, don't understand Reply with quote

Someone_Somewhere: I'm determined to follow your logic but I cannot see why, for example where you say
"From 1-st 3x3 box we know that it has to be in r1c1 or r1c4. So it can't be in r1c9. "

First, I think you mean 'From 1-st 3x3 box we know that it has to be in r1c1 or r1c**3**'

Secondly, your logic escapes me - there can also be 4s in row 2, c1 and 3, and r 3, c3... therefore I see no reason to exclude the 4 from row 1 c9!

Do you use Skype? I'd love to talk to you about this . My Skype name is poppapinebluff
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someone_somewhere



Joined: 07 Aug 2005
Posts: 275
Location: Munich

PostPosted: Fri Dec 30, 2005 9:17 am    Post subject: Reply with quote

Hi,
Sorry, I have Skype not installed.
I will let you know, if and when I install it.

Hope, you solved menwhile the Sudoku puzle.
I can only recommand you:
- the usage of the "candidate table", till you can solve puzles without it.
- the reading and training of the "solving techniques":
Row on 3x3 Block interaction
Column on 3x3 Block interaction
3x3 Block on Row/Column
Hidden Pair in Row, Column or 3x3 block
Naked Pair in Row, Column or 3x3 block
Hidden Triple in Row, Column or 3x3 block
Naked Triple in Row, Column or 3x3 block
Hidden Quadruples in Row, Column or 3x3 block
Naked Quadruples in Row, Column or 3x3 block
X-Wing on Row or Column
XY-Wing
Turbotfish
Swordfish on Row or Column

Jellyfish on Row or Column and
Squirmbag on Row - are not so important, in my opinion

and if you are mastering also the "double implication" technique (or a similar/equivalent one), there will be no Sudoku's left that you can not crack if you work long enough on them ...

see u,
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David Bryant



Joined: 29 Jul 2005
Posts: 559
Location: Denver, Colorado

PostPosted: Fri Dec 30, 2005 9:49 pm    Post subject: Someone_Somewhere had it right ... Reply with quote

PoppaPoppa wrote:
Code:
070 520 630
050 000 070
900 008 002
017 004 000
090 000 060
000 800 310
109 600 005
040 000 096
086 095 003

sorry, Munich, I don't understand. I don't see a naked pair of 4 5 atr3c7 - there is also a possible 9 there, nicht wahr? ...
I'm determined to follow your logic but I cannot see why,

Hi, PoppaPoppa! Happy New Year!

Someone_Somewhere had it nailed -- let me take a stab at it.

First, there cannot be a "9" at r3c7 because of the "9" at r3c1. Let's take a look at the initial possibilities in the top right 3x3 box:
Code:
   6      3    1489
  489     7    1489
  145     45     2

Now there can't be a "1" in r3c7, because if there were it would be impossible to place a "1" in the bottom right 3x3 box. So there's a pair {4, 5} in r3c7 & r3c8. Eliminating the "4" from the other 3 unresolved cells in the top right 3x3 box gives us this revised matrix:
Code:
   6      3     189
   89     7     189
   45     45     2

The only possibilities at r4c9 are {8, 9} -- you have {1, 4, 7} in row 4, and {2, 3, 6, 5} in column 9. So you can see a triplet {1, 8, 9} in r1c9, r2c9, & r4c9, leaving the hidden pair {4, 7} in r5c9 & r6c9. This means that r6c6 is the ONLY spot in which the "9" in row 6 can go. dcb
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PoppaPoppa



Joined: 06 Nov 2005
Posts: 21
Location: Arkansas USA

PostPosted: Sat Dec 31, 2005 6:44 pm    Post subject: Happy New Year Reply with quote

Thanks David I finally got it with the help of several folks who I thanked in another thread - Happy New year to you too!
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alanr555



Joined: 01 Aug 2005
Posts: 193
Location: Bideford Devon EX39

PostPosted: Wed Mar 01, 2006 12:48 am    Post subject: Reply with quote

We appear not to have heard from our Munchen friend for a while.
He will be missed. Meanwhile it is good to see some newcomers
engaging with the leading edge - in addtion to our Colorado friend
who is a real mainstay to this forum.

Alan Rayner BS23 2QT
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