# Extended Cross : ATTN Chris



## pjk (Jul 2, 2006)

I was reading up on this page (by Chris Hardwick):
http://www.speedcubing.com/chris/ec-strategy.html

When you use this, can you solve this 90% of the time and see it during pre-inspection? Thanks


----------



## cmhardw (Jul 4, 2006)

Hey Patrick,

I have three kinds of solves that I consider extended cross solves. These are 1) partial extended cross, 2) Petrich (2x2x2, then edges), and 3) direct solve extended cross.

Partial extended cross solves are when I can see during inspection the moves required to solve the extended cross, minus one of the 4 edges. I then either solve some of the F2L and later solve that last edge, or spot that edge at the end of the partial solve, and place it to from a complete extended cross.

Petrich is when I can spot during inspection the moves necessary to solve the 2x2x2 while leaving the other 2 edges in a good position to solve in 3-4 moves after the 2x2x2. I sometimes can work in one or both of those edges as I am solving the 2x2x2, but usually I just do the 2x2x2 and then those two edges after.

Direct solve extended cross is exactly what it sounds like, I can see all of the moves to the solution during inspection, and just execute those moves when the timer starts, and look for my next pair as I do that.

When I solve for only one color cross, I can find an extended cross between 28%-30% of the time and will solve it that way. Given that I actually use dual solving, so I always solve either white or yellow, that means I solve an extended cross 1-(1-0.30)^2=51% of the time in theory. In practice it does seem that very close to half the time I am doing one of my three definitions of what an extended cross is. I don't see the direct solve as often as the other two, but sometimes the start of a Petrich of partial extended cross is in fact the start of the direct solve, so I will do direct solve even though I only saw the 2x2x2, or a partial, during inspection.

90% though? No way. If I solve a cross on all 6 colors then given my roughly 30% max ability to spot an Xcross on one color I would have a 1-(1-0.3)^6=88% chance to solve an Xcross on any given solve, but I am not color neutral, I only can solve white and yellow with equal proficiency. I don't see myself making the switch to being completely color neutral any time soon.

Hope this helps, if I wrote that I can solve an Xcross 90% of the time on my site I'll take it off because that's not true. I'll look for it, but if you did see it somewhere let me know, so I can change that.

Chris


----------



## pjk (Jul 4, 2006)

Hey Chris,
Thanks for the help. It didn't say 90% anywhere, was just wondering if you could solve it most of the time, or it was like 1 out of 3, and whatnot. I'm going to work on this, it can really cut down on my times. Thanks
Pat


----------



## MasterofRubix (Oct 8, 2006)

Hi, im still working on my speed and consistency and i was wondering if extended cross is worth practicing, considering i dont have pre-inspection.


----------



## Johannes91 (Oct 8, 2006)

I don't think it's a good idea if you always solve without inspection time.


----------



## pjk (Oct 8, 2006)

Yeah, I agree with Johannes, do the X-cross without inspection is pretty much impossible. MasterRubiks: What don't you work on doing it with inspection?


----------



## MasterofRubix (Oct 8, 2006)

well i could, its just that i dont plan on going to an international competition any time soon so i never really practiced inspection. i sometimes do it for the weekly competitions on the forum but other than that, all my records have been achieved without inspection.


----------



## pjk (Oct 8, 2006)

There are non-inspection records as well. The idea is to solve the cube as quick as possible, and looking at it may take a few seconds off. Why not look at it?


----------



## MasterofRubix (Oct 9, 2006)

i guess i should start... but what exactly am i supposed to look at and how do i organize all the information in my head.


----------



## Stefan (Oct 9, 2006)

> _Originally posted by PJK_@Oct 8 2006, 08:54 PM
> *The idea is to solve the cube as quick as possible, and looking at it may take a few seconds off. Why not look at it?*


Because it's cheating?


----------



## AvGalen (Oct 9, 2006)

I have never heard of anyone beside magicians and "the behind his back guy" that solved a randomly scrambled cube (3x3x3 that is) without looking at it. However I think it could be possible. Flying ponies for everyone that can do that in at least 5 different ways within a minute.


----------



## pjk (Oct 9, 2006)

MasterofRubiks: At competitions you get a 15 second preinspection time. Typically, people can find the entire cross, and sometimes the first pair. To practice this, you can work on looking at the cube (for as long as you need) until you can do the cross without looking. The cross can be made in 8 moves or less no matter how scambled the cube is. With practice, you can get it down under 15 seconds.

Stefan: You know more about this than me.... but how is it cheating? That is official cubing standards, isnt it?

Avgalen: Yeah, I agree. However, technically, if the cube is mixed up, and you didn't look at it, the odds of you getting it right are 1 out of 43 quadrillion (or whatever total combos it is). So it is doubtful that you can do it without looking.


----------



## DDRKirby(ISQ) (Oct 10, 2006)

> _Originally posted by PJK_@Oct 9 2006, 05:35 PM
> * Avgalen: Yeah, I agree. However, technically, if the cube is mixed up, and you didn't look at it, the odds of you getting it right are 1 out of 43 quadrillion (or whatever total combos it is). So it is doubtful that you can do it without looking. *


 braiile cube? =p

x-cross is hard...-_-; but cool when you can do it, even once in a while. something extra to do after you've learned other stuff.

even if you were completely color neutral, it wouldn't necessarily help all -that- much, because you might have to go "look at white...k crap dont see xcross...look at yellow...crap dont see xcross...look at orange....ah oh $^@& 5 seconds left"

im imagining chris that in being white/yellow color neutral you can look for xcross for white+yellow both at the same time so you dont run into that...?


----------



## AvGalen (Oct 10, 2006)

PJK: I was preparing for a "Stefan Pochmann" reply. I didn't say "without looking", I said "without looking at it", just as you said in your post. This leaves possibilities like looking away from it (but in a mirror), braille, picture of the scrambled cube, etc.

Back on topic: Dan Harris has a nice piece about "the cross" on his site, as do others. Where could one find other tutorials about the x-cross?


----------



## pjk (Oct 10, 2006)

Oh, okay, np, haha. I now realize a little more why the english language is so complicated, especially online. For info on the x-cross, see the first post in this thread, to Chris's site.


----------



## AvGalen (Oct 10, 2006)

Apperantly: "the english language is so complicated, especially online" that you missed one word: "other"


----------



## cmhardw (Oct 10, 2006)

> *im imagining chris that in being white/yellow color neutral you can look for xcross for white+yellow both at the same time so you dont run into that...?*



Yeah I do usually just look for blocks with either a white or yellow sticker somewhere on that block. This could either be a partial piece for building a 2x2x1 on the D layer, or it could be a corner/edge pair.

I do sometimes find a good cross on one color, but then with like 5 seconds left I spot an Xcross on the other color. In those cases I sometimes just say it's not worth it, as I couldn't plan the Xcross in 5 seconds. But often I do switch and plan as fast as I can, even if I spot it in the last few seconds. That's probably not the best idea, but I have had fast solves where the switch to Xcross did help me speed up, say if the cross really wasn't all that great.

I just look for blocks made up of a corner and an edge, and if I spot one I look for either a white or yellow sticker somewhere on that block. I never really think that I'm examining for solely one color, then switch. I do sort of look at both at once until I see something that makes me like one color over the other. At that point I definitely do ignore the other color, or at least try my best to, in order to examine the one color I am focusing on for the solve.

Chris


----------



## AvGalen (Oct 11, 2006)

Now THAT was what I call a great explanation of the steps that go through a speedcubers mind during inspection!


----------



## DDRKirby(ISQ) (Oct 12, 2006)

> _Originally posted by cmhardw_@Oct 10 2006, 05:47 PM
> *
> 
> 
> ...


 yeah i forgot about the whole "see a 1x1x2 block->lets do xcross!" thing. been awhile since I've tried any xcross.

actually its now been a while since i've cubed at all. finger infection+surgery =/

its better now. still kinda stiff tho. but in a few weeks itll be fine.


----------



## MasterofRubix (Oct 12, 2006)

crap, i hope you feel better soon. i cant even imagine going through one day without cubing. 

I dont understand why some people dont like to do the x-cross. anyone wants to elaborate?


----------



## DDRKirby(ISQ) (Oct 12, 2006)

it's hard. :lol:


----------



## Stefan (Oct 12, 2006)

> _Originally posted by PJK_@Oct 9 2006, 05:35 PM
> * Stefan: You know more about this than me.... but how is it cheating? That is official cubing standards, isnt it?
> *


 Yes it is. But even though during inspection you don't twist the cube, you're already solving it in your head and you also orient the cube as a whole. That's why there are people who say it's cheating, because you start solving before the timer runs.


----------



## pjk (Oct 12, 2006)

Stefan: But techically, isn't solving the cube considered moving it and get all the colors on each side accordingly? The way I look at the inspection is more planning out what to do, not nescessarily solving it. And who are the ones calling it cheating? The ones who don't solve?


----------



## MasterofRubix (Oct 13, 2006)

Well i for one think that in a way it is cheating. my times are always 20-22 with inspection and sub-25 in general without. so inspection does help.


----------

