# Help for edges



## jackolanternsoup (Mar 16, 2008)

I'm learning to solve 4x4x4s BLD and doing all the bits separate i've got the corners to a very high success rate and the centers sort of almost there.. both together the closest I've got is accidently doing one of the commutators the wrong way so corners and all but 3 centres were right. 

But now i would like to learn edges.

I've done a few sighted edge solves with commutators but still am not entirely sure how to do it without an average of 4 setup moves.. But I guess that's practice?

anyway, i need to know how you find out if you've got OLL or PLL parity and how to make the parity appear in a fixed place and also what good memory method i can use for the edges. 
I already use a sort of kinesthetic method for CP, visual for CO, P-A-O for centres and I'm not very good with number memo so what other method can i use for the edges?


----------



## Pedro (Mar 16, 2008)

you can use P-A-O

I think PA is better, since you memorise in pairs, which is good if you're using commutators, since each 3-cycle is your starting position + 2 other pieces


you shouldn't need more than 2 setup moves...the worst cases are 2 setup moves, Chris told me...

did you read Chris guide? it's pretty good

the basics is that you must have 2 pieces interchangeable in one layer (meaning you can "shoot" one to the other if you turn that layer) and the other piece out of that layer

so, you shoot the "lone edge" (the piece out of the working layer) to it's spot, interchange the 2 pieces, undo first part, undo second part

there are many types of commutators, and all you gotta do is be able to reflect them across the cube...you can also turn the cube to get the pieces into a position where you can "see" the commutators better (I do that a lot)

it's just practice...when I started seriously doing 4x4 bld, I was mainly concerned about the centers, as they were harder for me at the time...

but now I got good at centers, and most of my DNFs have more edges incorrect than centers 

about the parity, you don't have "OLL parity" or "PLL parity"
I use the "pure" parity fixer, which swaps the 2 UF edges
r2 B2 U2 l U2 r' U2 r U2 F2 r F2 l' B2 r2 (all lower case letters meaning just slice turns)

sometimes I set-up the 2 final pieces into UF and fix them directly...sometimes I swap the 2 UF edges and do a 3-cycle to fix them all

Chris guide: http://www.speedsolving.com/showpost.php?p=1601&postcount=12


----------



## jackolanternsoup (Mar 17, 2008)

thanks a bunch but still, how do we know whether we've got parity in the memo phase?

Yeah i read it a while ago... it's good i kinda understand it better now  

I find edges more tough because of the lack of freedom compared to centers.

Oh another question, what should i do if i end up with about 2-3 pairs that only need to switch with each other. I got this during my sighted edge solves it was really weird. to solve it i had to cause a sort of parity...


----------



## Kenneth (Mar 17, 2008)

Pedro said:


> about the parity, you don't have "OLL parity" or "PLL parity"
> I use the "pure" parity fixer, which swaps the 2 UF edges
> r2 B2 U2 l U2 r' U2 r U2 F2 r F2 l' B2 r2 (all lower case letters meaning just slice turns)




Learn to use this one instead:

(x2) r2 U2 r' U2 l U2 l' U2 (x) U2 l' U2 r' (x) (12)

It's the shortest two edge swap there is (found by me =)

Four?, then this (or mirror) may come in handy:

r' U2 r2 U2 r U2 r' U2 r U2 r2 U2 r' (13)

Only r/r'/r2 + U2 turns.


----------



## Pedro (Mar 17, 2008)

wow, Kenneth!

I will surely learn those 



jackolanternsoup said:


> thanks a bunch but still, how do we know whether we've got parity in the memo phase?
> 
> Yeah i read it a while ago... it's good i kinda understand it better now
> 
> ...



you know there is parity when you're left with a piece on it's own...you have your starting position and just another edge to "cycle"

it's one of those pairs you mentioned

when I have that, I usually do 3-cycles to solve them

like

if you have A <-> B and C <-> D, I'd do
A -> B -> C (solves B and shoots piece A to position C)
then
A -> D -> C (solves D and C, and of course A, which was at C position)


----------



## jackolanternsoup (Mar 17, 2008)

hmm.. yeah seems quite good then.. thanks a load for the help..

Cool algs Kenneth.. Thanks 

I shall try to be the first (i think) fellow to solve a 4x4x4 BLD before a 3x3x3 BLD lol.


----------

