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Marty R. · Posted: Wed Jul 02, 2008 4:33 am Post subject: July 2 VH

(Subject edited for correct date - keith)

This was definitely a change of pace from the last one. My solution was:

1) Five ERs

2) M-Wing with pincer extension

3) XY-Wing Chain (some call it an extended XY-Wing) with pincer coloring

Maybe there was one X-Wing which could have killed it off, but I don't look for them except as a last resort.

Asellus · Posted: Wed Jul 02, 2008 8:49 am Post subject:

I believe you mean "July 2".

I try to stick with the 3 VH techniques on these... to make it a challenge. I used 2 X-Wings then an XY Wing.

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

Something must be wrong when I come up with the least number of solutions.

But anyway: I found a very destructive x-wing on<6> that left an xy-wing on <146>.

tlanglet · Posted: Wed Jul 02, 2008 12:18 pm Post subject:

For me it was also the x-wing on <6> that opened the xy-wing on <146>.

Ted

George Woods · Joined: 28 Mar 2006 Posts: 304 Location: Dorset UK

nataraj · Posted: Wed Jul 02, 2008 5:33 pm Post subject:

Yellow is the color of my true love's hair...

And 6 is the number. Plus the xy-wing afterwards.

There is also a jellyfish (a rare species: 5 in rows 2,3,6,7 is confined to columns 3,4,6,8 ) that removes 5 from r9c6 and r1c8. That does not solve the puzzle, unfortunately. But 5 comes before 6 and today I checked them in sequence 1,2,3 ...

Marty R. · Posted: Wed Jul 02, 2008 5:48 pm Post subject:

Clement · Posted: Wed Jul 02, 2008 6:39 pm Post subject: Daily Sudoku: Wed 2 Jul-2008 VH

I dont know whether I have grasped the BUG principle. This time again it solved the puzzle quite easily. This how it goes: 5 appears THREE TIMES in row 2 {58, 568, 56} and resides in a three candidate cell r2c6(568), the other undecided cells r2c3 & r2c8 have TWO candidates. Accordingly 5 goes in r2c6 solving the puzzle. Is that true? How can this be explained/proved?

storm_norm · Joined: 18 Oct 2007 Posts: 1741

using the draw play, I found the x-wing on 5 first, probably didn't have all the basics done to that point. but it took a while to see all the eliminations from the 6 x-wing.

wapati

nataraj

Asellus · Posted: Wed Jul 02, 2008 10:15 pm Post subject:

Asellus · Posted: Wed Jul 02, 2008 10:26 pm Post subject:

nataraj,

Regarding Jellyfish, they really aren't all that rare. It's just that we usually notice the smaller complementary fish instead. As Myth Jellies has pointed out, your basic fish are constraint sets. And, they always occur in complementary groups of two or more. You might have a Swordfish and a Jellyfish together, or a Swordfish and two X-Wings, for instance. What is rare is two complementary Jellyfish (or a Jellyfish and a "5-Fish").

In this puzzle, I noticed the complementary X-Wing in c15 rather than the Jellyfish. And, like you I started with the lower numbers in sequence so found the (apparently unneeded) 5 X-Wing before the more useful 6 X-Wing.

nataraj · Posted: Thu Jul 03, 2008 6:42 am Post subject:

Thanks, Asellus, for the explanation.
Funny I should have seen that complex jellyfish and not seen the simple x-wing. Must have looked at the grid cross-eyed. I'll close one eye from now on to safeguard against such lapses Wink

George Woods · Joined: 28 Mar 2006 Posts: 304 Location: Dorset UK