"too hard" ( not ! ) — joel64 # 198 # 37

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"too hard" ( not ! ) — joel64 # 198 # 37

Postby Pat » Fri Jan 25, 2013 8:27 am


    1..2....3.4..5......6..12..5..7..6...8.....7...1..8..2..98..4......7..5.8....3..1

    [ play ]

Code: Select all

 1 . . | 2 . . | . . 3
 . 4 . | . 5 . | . . .
 . . 6 | . . 1 | 2 . .
-------+-------+------
 5 . . | 7 . . | 6 . .
 . 8 . | . . . | . 7 .
 . . 1 | . . 8 | . . 2
-------+-------+------
 . . 9 | 8 . . | 4 . .
 . . . | . 7 . | . 5 .
 8 . . | . . 3 | . . 1

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Re: "too hard" ( not ! ) — joel64 # 198 # 37

Postby 7b53 » Fri Jan 25, 2013 7:20 pm

this puzzle can be solved by basic techniques. it doesn't means it is easy.
many players are not used to spotting hidden subsets for whatever reasons.
and supposed the challenge is to solved it without any pencil-marked.
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Re: "too hard" ( not ! ) — joel64 # 198 # 37

Postby Marty R. » Fri Jan 25, 2013 10:03 pm

I'll readily call anyone a genius with a photographic memory if they can solve this without PMs.

Yes, basics, but one must look extremely carefully for the quads.
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Re: "too hard" ( not ! ) — joel64 # 198 # 37

Postby JasonLion » Sat Jan 26, 2013 1:13 am

Quads? I saw just three triples, a couple of locked candidates, and singles.
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Re: "too hard" ( not ! ) — joel64 # 198 # 37

Postby Marty R. » Sat Jan 26, 2013 2:24 am

JasonLion wrote:Quads? I saw just three triples, a couple of locked candidates, and singles.


Not a shock. I constantly miss stuff that's there right in front of my nose. :oops:
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Postby Pat » Sun Jan 27, 2013 9:51 am

JasonLion wrote:three triples

yes, 3 heavy moves
— i thought that's high enough to be unusual and interesting
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Re: "too hard" ( not ! ) — joel64 # 198 # 37

Postby 7b53 » Sun Jan 27, 2013 8:33 pm

It is highly unusual needing three triples.
Plus the way those hidden triples are form makes it harder to spot.
If you noticed the first two are form pretty much in an identical way.
And yes, is a very interesting one.
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Postby Pat » Mon Jan 28, 2013 1:23 pm

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Re:

Postby JasonLion » Mon Jan 28, 2013 2:34 pm


That uses hidden triples as well as naked triples.

<withdrawn>
Last edited by JasonLion on Thu Jan 31, 2013 3:02 pm, edited 1 time in total.
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Re: "too hard" ( not ! ) — joel64 # 198 # 37

Postby 7b53 » Tue Jan 29, 2013 1:36 pm

one of the greatest enemy for non pencil-marker is spotting naked subsets.
just a naked pair can takes forever. not to mention naked triple,quad. or maybe is just for me.

Pat wrote:joel64 # 163 # 40

for some reason, i like the previous one better.
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Re: "too hard" ( not ! ) — joel64 # 198 # 37

Postby keith » Wed Jan 30, 2013 6:10 pm

Marty R. wrote:I'll readily call anyone a genius with a photographic memory if they can solve this without PMs.


Well, I don't know about that, but I did solve it without PMs. I must admit to staring at it for a long time!

If you don't try to solve without PMs, it's kind of hard to explain. It works by finding the hidden subsets rather than the naked subsets. First, take a look at C3. Note the cells which are not 578; they must be 234. That solves a couple of cells, R2C14.

Now, look at R3 for the cells that are not 357. They must be 489. That solves R1C2 as 9 and, more importantly, fixes 4 in B6C9.

Now, look at B4 for the cells that are not 679. They must be 234. This fixes 4 in B4C3. Looking at which squares can be 4 solves the puzzle.

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Re: "too hard" ( not ! ) — joel64 # 198 # 37

Postby Marty R. » Wed Jan 30, 2013 7:16 pm

Well, I don't know about that, but I did solve it without PMs. I must admit to staring at it for a long time!


I'll stand by my statement. It's very impressive as far as I'm concerned.
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Re: "too hard" ( not ! ) — joel64 # 198 # 37

Postby eleven » Wed Jan 30, 2013 8:39 pm

Maybe it helps, when you see them marked.
Code: Select all
 1 . . | 2 . . | . . 3
 . 4 . | . 5 . | . . .
 . . 6 | . . 1 | 2 . .
-------+-------+------
*5 . x |*7 . . | 6 . .
 .*8 x | . . . | .*7 .
 . . 1 | . . 8 | . . 2
-------+-------+------
 . . 9 | 8 . . | 4 . .
 . . x | .*7 . | .*5 .
*8 . . | . . 3 | . . 1

The 578 all see the cells marked with x. As Keith says, it needs some time to spot it. But it's the same for patterns in pencilmark grids.
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Re: "too hard" ( not ! ) — joel64 # 198 # 37

Postby keith » Wed Jan 30, 2013 9:29 pm

OK,

I'll take eleven's cue and spell it out.

Code: Select all
 1 . y | 2 . . | . . 3
 . 4 y | . 5 . | . . .
 . . 6 | . . 1 | 2 . .
-------+-------+------
*5 . x |*7 . . | 6 . .
 .*8 x | . . . | .*7 .
 . . 1 | . . 8 | . . 2
-------+-------+------
 . . 9 | 8 . . | 4 . .
 . . x | .*7 . | .*5 .
*8 . y | . . 3 | . . 1

The cells y are 578. The cells x are 234. Solving 2 and 3 in R2.

Code: Select all
 1 . . | 2 . . | . .*3
 2 4 . |*3*5 . | . . .
 y y 6 | x x 1 | 2 x y
-------+-------+------
 5 . . |*7 . . | 6 . @
 . 8 . | . . . | .*7 @
 . . 1 | . . 8 | . . 2
-------+-------+------
 . . 9 | 8 . . | 4 . .
 . . . | .*7 . | .*5 .
 8 . . | . . 3 | . . 1

The cells y are 357. The cells x are 498. @ is where 4 must be in B6C9. Solving 9 in R1C2.

Code: Select all
 1 9 . | 2 . . | . . 3
 2 4 . |*3*5 . | . . .
 . .*6 | . . 1 | 2 . y
-------+-------+------
 5 x x@|*7 . . |*6 . @
 . 8 x@| . . . | .*7 @
 . . 1 | # # 8 | . . 2
-------+-------+------
 . .*9 | 8 . . | 4 . .
 . . . | . 7 . | . 5 .
 8 . . | # # 3 | . . 1

The cells x are not 679. They are 234. The cells @ must contain 4 in B4C3 and B6C9. You can solve 4 in B7. Then look at the pattern for 4 in B58 (#) and solve 4 in B2. The puzzle is done.

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Re: "too hard" ( not ! ) — joel64 # 198 # 37

Postby 7b53 » Tue Feb 05, 2013 3:04 am

keith wrote:I must admit to staring at it for a long time!

you're not the only one Keith. maybe I was staring it longer than you.
trying to find pair at the beginning..... none !
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