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Jan 21 Just for Interest

 
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kragzy



Joined: 01 May 2007
Posts: 112
Location: Australia

PostPosted: Mon Jan 21, 2008 1:10 am    Post subject: Jan 21 Just for Interest Reply with quote

I reached this point and couldn't work out what I was missing:

Code:

+-----------------+-------------+-----------------+
| 246  2469  2469 | 3   289  14 | 7    1259  1589 |
| 3    1     8    | 29  7    5  | 26   2469  49   |
| 5    7     249  | 6   289  14 | 238  129   1389 |
+-----------------+-------------+-----------------+
| 2467 23469 5    | 8   1249 67 | 36   1679  139  |
| 1    34689 469  | 59  49   67 | 3568 5679  2    |
| 2678 2689  269  | 259 129  3  | 4    15679 1589 |
+-----------------+-------------+-----------------+
| 24   24    1    | 7   5    8  | 9    3     6    |
| 9    5     3    | 4   6    2  | 1    8     7    |
| 68   68    7    | 1   3    9  | 25   245   45   |
+-----------------+-------------+-----------------+


Eventually I spotted the hidden pair in R5. No doubt others saw it straight away.

Thought I'd post this just in case someone else gets stuck at this point, and also for the simple pleasure of posting a "non VH" thread!!

Cheers
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ravel



Joined: 21 Apr 2006
Posts: 536

PostPosted: Mon Jan 21, 2008 3:04 pm    Post subject: Reply with quote

Hidden pairs often can be spotted easier without pencilmarks.
Code:
 +-------+-------+-------+
 | . . . | 3 . . | 7 . . |
 | 3 1<8>| . 7 5 | . . . |
 | 5 7 . | 6 . . | . . . |
 +-------+-------+-------+
 | . . 5 |<8>. . | . . . |
 | 1 . x | x x x | . x 2 |
 | . . . | . .<3>| 4 . . |
 +-------+-------+-------+
 | . . 1 | 7 5 8 | 9<3>6 |
 | 9 5<3>| 4 6 2 | 1<8>7 |
 | . . 7 | 1 3 9 | . . . |
 +-------+-------+-------+

Some samples:
This puzzle can be solved with singles and 2 easy-to-spot hidden pairs (but looks hard with full pencilmarks).
Code:
 +-------+-------+-------+
 | . 1 . | . . . | . . . |
 | . . 6 | . . . | . . . |
 | . 2 . | 8 . . | 4 3 . |
 +-------+-------+-------+
 | . . . | 5 . 9 | . . 6 |
 | . 3 . | 7 . 8 | . . . |
 | . . 4 | . . . | 2 8 . |
 +-------+-------+-------+
 | 5 4 . | . . . | . . 1 |
 | . . . | . . 3 | . . 2 |
 | . . . | . . . | 6 9 . |
 +-------+-------+-------+
>>> play online

Here are 3 hidden pairs in the grid. The two with same numbers are not hard to spot:
Code:
 +-------+-------+-------+
 | . . 1 | 2 . . | . 3 . |
 | . . 4 | 5 . 6 | . . 1 |
 | 6 5 . | 1 . . | . . . |
 +-------+-------+-------+
 | 7 8 6 | . . . | . 5 . |
 | . . . | . . . | . . . |
 | . 4 . | . . . | 3 6 8 |
 +-------+-------+-------+
 | . . . | . . 2 | . 7 3 |
 | 2 . . | 3 . 9 | 8 . . |
 | . 6 . | . . 1 | 2 . . |
 +-------+-------+-------+ (JPF)
>>> play online

Here even 2 hidden triples are not hard to spot (and 2 hidden pairs)
Code:
 +-------+-------+-------+
 | . . . | . . . | . . . |
 | . 1 . | 2 3 4 | . 5 . |
 | . . 6 | . . . | 1 . . |
 +-------+-------+-------+
 | . 4 . | 5 . 2 | . 1 . |
 | . 7 . | . . . | . 2 . |
 | . 3 . | 1 . 8 | . 6 . |
 +-------+-------+-------+
 | . . 7 | . . . | 4 . . |
 | . 2 . | 6 9 5 | . 7 . |
 | . . . | . . . | . . . |
 +-------+-------+-------+ (JPF)
>>> play online

[Edit:]Added play online links.
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sdq_pete



Joined: 30 Apr 2007
Posts: 119
Location: Rotterdam, NL

PostPosted: Mon Jan 21, 2008 9:04 pm    Post subject: Reply with quote

Quote:
No doubt others saw it straight away

It certainly took me quite some time to spot the 38 hidden pair. I was "reduced" to systematically scanning for anything occurring twice or three times and then checking if perchance it had a companion. The 38 then inevitably arose. But I certainly would never have spotted it just by staring at the puzzle hoping for inspiration.

Peter
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kragzy



Joined: 01 May 2007
Posts: 112
Location: Australia

PostPosted: Tue Jan 22, 2008 1:01 am    Post subject: Reply with quote

It was the 45679 quintuplet in R5 that I saw first. I mostly seem to see the bigger sets before the smaller; don't know why, just a wierd quirk of my twisted logic.
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sheryl



Joined: 24 Sep 2007
Posts: 64
Location: New York

PostPosted: Tue Jan 22, 2008 3:14 am    Post subject: hidden pair Reply with quote

Kragzy, thank you thank you. i've been looking at this puzzle for quite a while and just didn't see anything until you said the magic words "hidden pair in r5"!
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Marty R.



Joined: 12 Feb 2006
Posts: 5732
Location: Rochester, NY, USA

PostPosted: Tue Jan 22, 2008 4:50 am    Post subject: Reply with quote

kragzy wrote:
It was the 45679 quintuplet in R5 that I saw first. I mostly seem to see the bigger sets before the smaller; don't know why, just a wierd quirk of my twisted logic.


Just yesterday I wrote the following in another thread:

"In my 2+ years, I've never found a hidden anything bigger than a single. I'll take a naked quint over a hidden pair anytime."
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