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

Sometimes the VHs are "very easy" but are classified as VHs because they contain an "advanced step" - which may be nothing more challenging than an easy to spot X wing. I tried today's Hard puzzle, just for the helluvit, and found it very challenging (actually I'm still working on it). Try it for a change - without any "advanced steps".

Asellus · Posted: Tue Oct 16, 2007 1:21 am Post subject:

I agree. The "key" step is something very basic (hence "Hard" rather than "Very Hard") but not so easy to spot.

Captain Pete · Joined: 09 Jun 2007 Posts: 55 Location: Oley, PA

I give up... what is the key I'm missing?

Marty R. · Posted: Tue Oct 16, 2007 4:58 am Post subject:

nataraj · Posted: Tue Oct 16, 2007 6:25 am Post subject:

don't know if there was one single "key" step.
The ones that took me longest to spot were

SPOILER ALERT

- the "4" confined to col 1 in box 7, also "4" confined to box 1 in col 2
- the 12789 vs. hidden pair 35 in col 9

END SPOILER ALERT

all in all, a rather tough "hard"

duffy · Joined: 13 Sep 2007 Posts: 26 Location: Toronto Canada

Now that the "spoiler" is out there, I have to say that the positioning of the pair in c9 among an especially large number of alternative candidates was truly difficult for me to spot. (I found it after resorting to a stategic "trial and error" approach.) Since the pair stradles a box boundary, I found it at first surprising to note the effect it had on the available 9's in r6, after which the solution was straightforward. I think it was surprising because this kind of interaction has been uncommon in my obsessive (according to my family) experience.
Rolling Eyes

Don D.

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

Each to his own problem. I agree it was tough for "Hard" but I often find this to be so, it taking longer over some "hard" than some "V Hard".

For me the breakthrough that took some time to spot was recognising the "attack of 35s" on column 9 - thereafter it wasn't too time consuming!

sweedy · Joined: 21 Oct 2005 Posts: 3 Location: Zurich

I really gave up on that one yesterday after not seeing the solution after a while.. I did spot the hidden 35 pair in c9 but still I don't see how this helps!
I don't see how the "4" confined to col 1 in box 7, or how the "4" is confined to box 1 in col 2..
what effect does this 35-pair have on the 9s in r6?? help!!!

duffy · Joined: 13 Sep 2007 Posts: 26 Location: Toronto Canada

Sweedy,
Consider the point at which I got stuck:

duffy · Joined: 13 Sep 2007 Posts: 26 Location: Toronto Canada

In a rush, I often do something wrong: There should have been a 1 in r3c8 as follows:

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

Marty R. · Posted: Tue Oct 16, 2007 9:12 pm Post subject:

Asellus · Posted: Tue Oct 16, 2007 9:38 pm Post subject:

Yes... my "key" was the hidden {35} pair.

Sweedy,

I don't believe your question about the <4>s was answered. Once the <6> and <1> are solved in C6 of Box 8, the {16} locked pair occurs in R7C23 of Box 7. The only place left for <4> in Box 7 is then R78C1.