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June 6 VH

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andras

Joined: 31 Oct 2007
Posts: 56
Location: Mid Wales

Posted: Fri Jun 06, 2008 6:36 am Post subject: June 6 VH

A very straightforward one this time; solves a long way without any advanced techniques at all, and then an XYZ (on 4,6,7) and an XY (on 2,6,7) are all that are needed to solve it. I can't imagine there's a faster way than this! John

cgordon

Joined: 04 May 2007
Posts: 769
Location: ontario, canada

Posted: Fri Jun 06, 2008 12:39 pm Post subject:

I also used the <467> xyz wing but found this left a BUG + 1 in Box 1 which forces the <2> into R1C1.

stevieboy

Joined: 25 Jan 2008
Posts: 31
Location: Michigan

Posted: Fri Jun 06, 2008 1:08 pm Post subject:

I arrived at this point:

Code:

+-------------+------------+--------+
| 2567 267 8 | 57 9 267 | 1 4 3 |
| 25 4 1 | 58 3 28 | 9 6 7 |
| 367 367 9 | 1 46 467 | 2 5 8 |
+-------------+------------+--------+
| 23 23 6 | 4 7 5 | 8 1 9 |
| 9 1 7 | 6 8 3 | 4 2 5 |
| 8 5 4 | 2 1 9 | 7 3 6 |
+-------------+------------+--------+
| 67 8 2 | 357 56 1 | 35 9 4 |
| 4 67 35 | 9 2 67 | 35 8 1 |
| 1 9 35 | 358 45 48 | 6 7 2 |
+-------------+------------+--------+

I noticed the same XYZ-Wing mentioned by andras, but wasn't sure whether it was "legitimate" (the same word I always seem to be using in my explanations!).

However, I did notice something else which turned out to be a puzzle-solver...it's LIKE a UR, but it's not really a rectangle(!). The <67> pairs in Rows 7 and 8, along with the <56> in R7C5 act like a UR, eliminating the '6' ...what is this really classified as?

Speaking of Wings....GO RED WINGS!!!!!!!

nataraj

Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria

Posted: Fri Jun 06, 2008 2:35 pm Post subject:

stevieboy wrote:

I noticed the same XYZ-Wing mentioned by andras, but wasn't sure whether it was "legitimate"

...

I did notice something else ...what is this really classified as?

stevieboy, the only reliable way to go beyond guessing and lucky strikes is dig just a little bit below the surface of things, i.e. to understand WHY an elimination can be made from a certain pattern.

If you are not sure whether the pattern in box 2/col 6 is really an XYZ wing and what it does, then try and re-create the logical steps. Finding the pattern is a crucial first step. This is the pattern:

Code:

267

46 467
--------

67

in row 3, the cells {46} and {467} might form an xyz-wing together with {67} in r8c6.

To prove that this is really an XYZ wing and that it really does something useful, one starts at the "lone" cell "67" outside the box where all the other cells are.

For this cell there are always exactly two possibilities. Just like here.
Either r8c6=6 or it is 7. If you can prove that both assumptions lead to the same result, you've won.
So, lets start with the first possibility:
a) r8c6=6. Then the target cell r1c6 cannot be 6 (why?)

Now the other possibility:
b) r8c6=7. Then r3c6 cannot be 7 (why?) and r3c5 and r3c6 form a naked pair 46 and thus r1c6 again cannot be 6.

Since both assumptions lead to the same result (r1c6 is not 6) you've found an XYZ wing, validated it and proved how it removes 6 from r1c6.

Once familiar with the technique, this verification takes only 5 seconds.
Of course, with enough practice, you'll be able to make the elimination without going thru the proof every time. Until then, as long as you are "not sure", there is no other way.

Your other "puzzle solver" is unknown to me. Try to go through the steps and prove how your elimination works. Which '6' is eliminated? From what cell? Why? There is a huge chance that the unique rectangle that is not a rectangle might turn out to be the same as dehydrated water: nothing. But if you can explain the path and the logical inferences, the elimination would be valid even if it has no name.

stevieboy

Joined: 25 Jan 2008
Posts: 31
Location: Michigan

Posted: Fri Jun 06, 2008 3:11 pm Post subject:

nataraj wrote:

Your other "puzzle solver" is unknown to me. Try to go through the steps and prove how your elimination works. Which '6' is eliminated? From what cell? Why? There is a huge chance that the unique rectangle that is not a rectangle might turn out to be the same as dehydrated water: nothing. But if you can explain the path and the logical inferences, the elimination would be valid even if it has no name.

Alright, nataraj, I'll do my best to explain what I "saw" -
The <67> to <67> Box 7 pairing (R7C1 to R8C2), leading to the <67> in R8C6, and, finally to the <56> (R7C5) in Box 8.

To me, this has the characteristics of a UR (Type 1?), but without it ACTUALLY being a rectangle. In looking at this, (please follow me on this!), I imagined shifting the <67> 's in Row 8 over to the left by ONE CELL, as if it WERE actually a rectangle.

As what you said earlier in your XYZ-wing explanation to me, I always thought if the pivot, and the pincers leading from it had "wing" characteristics, then the common pincer cell candidates can be eliminated. I know you told me a couple of days ago that this isn't always the case, and I've been trying to understand why....I'll keep your earlier reference handy. As far as the "possibilities" technique to solve these puzzle, I've been kind of lazy about doing that...I'm always trying to find "easier" ways to solve these things!!! Anyway, your input is always appreciated - keep 'em coming!

nataraj

Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria

Posted: Fri Jun 06, 2008 3:22 pm Post subject:

stevieboy wrote:

I'm always trying to find "easier" ways to solve these things!!! Anyway, your input is always appreciated - keep 'em coming!

In that case, I'll be glad to give one more bit of advice: beware of pretty words, imagined solutions and drawing conclusions from "as if"...

Good luck(you are sure to need it Smile

)

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Fri Jun 06, 2008 3:52 pm Post subject:

With pencil and paper it solved with basics only, but then I tried it on Draw/Play and needed the XYZ-Wing and BUG+1.

stevieboy

Joined: 25 Jan 2008
Posts: 31
Location: Michigan

Posted: Fri Jun 06, 2008 4:49 pm Post subject:

Gee, thanks!

storm_norm

Joined: 18 Oct 2007
Posts: 1741

Posted: Sat Jun 07, 2008 4:27 pm Post subject:

I am with marty, xyz-wing

then this BUG

Code:

.---------------.---------------.---------------.
|(2)56 26 8 | 57 9 27 | 1 4 3 |
| 25 4 1 | 58 3 28 | 9 6 7 |
| 37 37 9 | 1 46 46 | 2 5 8 |
:---------------+---------------+---------------:
| 23 23 6 | 4 7 5 | 8 1 9 |
| 9 1 7 | 6 8 3 | 4 2 5 |
| 8 5 4 | 2 1 9 | 7 3 6 |
:---------------+---------------+---------------:
| 67 8 2 | 37 56 1 | 35 9 4 |
| 4 67 35 | 9 2 67 | 35 8 1 |
| 1 9 35 | 38 45 48 | 6 7 2 |
'---------------'---------------'---------------'

the 2 in r1c1 is the odd man out, and r1c1 solves as 1.

cgordon

Joined: 04 May 2007
Posts: 769
Location: ontario, canada

Posted: Sat Jun 07, 2008 4:46 pm Post subject:

Quote:

I am with marty, xyz-wing
then this BUG

What about me?? I mentioned them first !!

I feel like Rodney Dangerfield.

Marty R.

Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA

Posted: Sat Jun 07, 2008 4:51 pm Post subject:

Quote:

I feel like Rodney Dangerfield.

At least you're on the right side of the daisies. Wink

storm_norm

Joined: 18 Oct 2007
Posts: 1741

Posted: Sat Jun 07, 2008 5:08 pm Post subject:

cgordon wrote:

Quote:

I am with marty, xyz-wing
then this BUG

What about me?? I mentioned them first !!

I feel like Rodney Dangerfield.

sorry, you are right. just north of the border in canada, cgordon deserves the props.

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