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Fin transport

 
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Marty R.



Joined: 12 Feb 2006
Posts: 5179
Location: Rochester, NY, USA

PostPosted: Sat Nov 13, 2010 7:44 pm    Post subject: Fin transport Reply with quote

This is something which I get to use just once in a while, but it's fun when it happens. It's a Finned X-Wing except the fin is not in a box housing the X-Wing. If the fin can be transported, then a cell which contains an X-Wing deletion and sees the transport-to cell cannot contain the X-Wing candidate.

This is the Brain Bashers Super Hard from April 3, after a Remote Pairs and Simple Coloring.

Code:

+-----------+------------+------------+
| 4  278 38 | 167 126 19 | 179 5  13  |
| 37 27  9  | 4   126 5  | 8   67 136 |
| 5  1   6  | 8   79  3  | 2   4  79  |
+-----------+------------+------------+
| 8  4   7  | 3   16  2  | 5   9  16  |
| 39 59  35 | 16  8   4  | 17  67 2   |
| 2  6   1  | 9   5   7  | 4   3  8   |
+-----------+------------+------------+
| 79 3   2  | 5   4   8  | 6   1  79  |
| 1  79  4  | 2   79  6  | 3   8  5   |
| 6  58  58 | 17  3   19 | 79  2  4   |
+-----------+------------+------------+

Play this puzzle online at the Daily Sudoku site

Columns 46 would be an X-Wing on 1 except for the extra 1 in r5c4. That 1 can easily be transported to r4c9. R1c9<>1 because it sees the new transport cell and would be deleted by the X-Wing.

There may well be other solutions; I didn't check once I noted this.
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tlanglet



Joined: 17 Oct 2007
Posts: 2461
Location: Northern California Foothills

PostPosted: Sun Nov 14, 2010 1:22 am    Post subject: Reply with quote

Marty,

I have used that type of step frequently and was told that it is called a Kraken fin; when used the pattern is a Kraken x-wing, Kraken swordfish, etc.

To me, it is just another "almost" pattern where deletions are possible if both the basic pattern and the "almost" condition make identical deletions.

Ted
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Marty R.



Joined: 12 Feb 2006
Posts: 5179
Location: Rochester, NY, USA

PostPosted: Sun Nov 14, 2010 2:23 am    Post subject: Reply with quote

Ted,

I learned this as "Fin transport" a few years years back when someone posted it and I haven't seen any talk about it since.

Coincidentally, just yesterday I happened to look up Kraken and what I saw, at least on the one site I checked, was much more complicated than this, such that I doubt I'd be able to recognize the pattern unless I put in a lot more time studying it.

Quote:
To me, it is just another "almost" pattern where deletions are possible if both the basic pattern and the "almost" condition make identical deletions.

That statement is true to a certain extent. However, once the pattern is recognized, the deletion can be made immediately without checking further because the pattern works every time.

On some other "almost" patterns, such as ANP and AXY, to name just two, you don't know whether both possibilities will have the same result. In effect, the "almost" has provided a starting point and each possibility needs to be tested to see what happens. So I don't think I'd put them in the same category.

Thanks and best regards,

Marty
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tlanglet



Joined: 17 Oct 2007
Posts: 2461
Location: Northern California Foothills

PostPosted: Sun Nov 14, 2010 3:00 am    Post subject: Reply with quote

Marty R. wrote:
Ted,

I learned this as "Fin transport" a few years years back when someone posted it and I haven't seen any talk about it since.

Coincidentally, just yesterday I happened to look up Kraken and what I saw, at least on the one site I checked, was much more complicated than this, such that I doubt I'd be able to recognize the pattern unless I put in a lot more time studying it.

Quote:
To me, it is just another "almost" pattern where deletions are possible if both the basic pattern and the "almost" condition make identical deletions.

That statement is true to a certain extent. However, once the pattern is recognized, the deletion can be made immediately without checking further because the pattern works every time.

On some other "almost" patterns, such as ANP and AXY, to name just two, you don't know whether both possibilities will have the same result. In effect, the "almost" has provided a starting point and each possibility needs to be tested to see what happens. So I don't think I'd put them in the same category.

Thanks and best regards,

Marty


Marty,

In you initial post you noted that you had to "transport" the fin. In many cases, transporting may involve numerous steps in which case no deletions are immediately obvious. Also, more than one transport strategy is sometimes required to obtain additional deletions that are also provided by the basic pattern.

Ted
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peterj



Joined: 26 Mar 2010
Posts: 974
Location: London, UK

PostPosted: Sun Nov 14, 2010 6:58 pm    Post subject: Reply with quote

I have always thought there was a useful distinction between kraken fish and "almost" fish.
A kraken fish being when the fin outside the box makes one or more of the fish eliminations using single digits strong links, grouped or otherwise i.e it is totally a single digit move.
An almost fish is one when the fin makes eliminations but using other xy logic i.e. some sort of chain etc.
Not sure my source for this belief!
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