# U2 for centers



## Stefan (Feb 7, 2008)

In Budapest I talked with Chris about blindsolving the 6x6 and I came up with the U2 method for centers.

Buffer: Ufl
Target: Ubr
Algorithm to swap buffer and target: U2

The centers on F, B, L and R can be solved like this:

(r' u* r) U2 (r' u* r)
(r d* r') U2 (r d* r')
(b' d* b) U2 (b' d* b)
(b u* b') U2 (b u* b')

Each of these solves three centers, the remaining four require an extra initial get-out-of-the-way setup move. The D centers need some other alg, but just one, as you can use a D turn setup move.


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## RobinBloehm (Feb 7, 2008)

what about U centers? Found the Set-Up-Moves for D-centers , but U-centers are quite heavy. Don't you need them? Or is there a very crazy alg you can't find out intuitively?


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## Stefan (Feb 7, 2008)

What's your D-centers solution? And I didn't mention the U-centers because, well, I forgot. There's a ten moves solution for them, though. The nine moves three-cycle similar to A-perm for 3x3, plus a U2.


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## RobinBloehm (Feb 7, 2008)

To shoot to Dbr I can use: (r F d2 F' r') U2 (r F d2 F' r')

The other D-centers with D moves


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## Pedro (Feb 7, 2008)

how do you solve U centers and D ones?


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## Stefan (Feb 7, 2008)

Here's the 3-cycle of U edges I mentioned before: (r b' r) f2 (r' b r) f2 r2. Combine that with a U2.


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## Stefan (Feb 7, 2008)

Wait! I forgot why I forgot. Now I remember why I forgot: I didn't forget. Shooting from U to U is unnecessary. That's why I didn't cover it. I think. Maybe it is necessary. Or not? Once you have a U center in the buffer, you do just a U2 turn to break into the cycle starting at the target. Unless that one already contains a U center, too. In which case you can do a single U turn and start using the other two U center positions as buffer and target. I didn't fully think this through, though. Maybe that's the reason I didn't publish this method earlier. I'm confused now. Great.


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## RobinBloehm (Feb 7, 2008)

Another idea would be that you start memorization of center-cycles at U always, so all cycles that include U-centers start with this U-piece. Then you do not have any problems because you do U, U' or U2 as the first move and undo it in the end of the cycle. That's really easy and fits into my way of memorization.

I think that's what you mean Stefan


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## Erik (Feb 7, 2008)

Lol, Stefan strikes again, first time I saw it (not reading the post yet): *smack head* why didn't I think of this?? It's 100x better than r2 xD. Stefan rocks  (Chris too!)


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## RobinBloehm (Feb 7, 2008)

Do you have got a better Setup for D-centers than I have posted above, Stefan?


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## Stefan (Feb 7, 2008)

RobinBloehm said:


> Do you have got a better Setup for D-centers than I have posted above, Stefan?


No, I didn't have any, and yours looks good. I think originally I thought about asking Per for an alg for it, as he might very well know a good one from his cage speedsolving method.


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## Stefan (Feb 7, 2008)

Btw, as said before, I made this up for 6x6. I think its new center type that the 4x4 doesn't have makes shooting to D easier. I have trouble visualizing it, though. Could someone please borrow me his 6x6 for a moment?


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## Pedro (Feb 7, 2008)

Stefan, how do you set-up centers like Lub or Fur?

I'm having some trouble with them...I thought about doing L or F, then a "normal" set-up...but you have to keep that L or F until you have done 2 "U2 cycles", or you'll mess up the edges...

do you have a better solution?


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## tim (Feb 7, 2008)

Pedro said:


> Stefan, how do you set-up centers like Lub or Fur?
> 
> I'm having some trouble with them...I thought about doing L or F, then a "normal" set-up...but you have to keep that L or F until you have done 2 "U2 cycles", or you'll mess up the edges...
> 
> do you have a better solution?



Have you thought about d/u as a "move out of the way"-move?


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## Pedro (Feb 7, 2008)

tim said:


> Pedro said:
> 
> 
> > Stefan, how do you set-up centers like Lub or Fur?
> ...



no...:O those are much better than R/F/L/B as "move out of the way"-moves 

great, Tim! that's why you're so good at 4x4 bld


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## tim (Feb 7, 2008)

Pedro said:


> tim said:
> 
> 
> > Pedro said:
> ...



I'm not good, Chris and Mátyás are good. Anyway, i'm going to play around with U2 in the train later. U2 seems quite nice, hopefully it's faster than commators for me.


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## Lucas Garron (Feb 7, 2008)

Erik said:


> Lol, Stefan strikes again, first time I saw it (not reading the post yet): *smack head* why didn't I think of this?? It's 100x better than r2 xD. Stefan rocks  (Chris too!)



Really? I smacked my head the second I saw his M2 page, but I think r2 will be nicer for centers. It's easier to execute r2 with free fingers, and for oblique centers, you only have 4 centers in the appropriate slice. Gah, why did our district come up with this silly concert??? :confused:


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## Pedro (Feb 7, 2008)

Lucas Garron said:


> Erik said:
> 
> 
> > Lol, Stefan strikes again, first time I saw it (not reading the post yet): *smack head* why didn't I think of this?? It's 100x better than r2 xD. Stefan rocks  (Chris too!)
> ...



U2 is also very easy to execute...

and what do you mean with that other part?
I was thinking about this and saw that U2 is way easier when it comes to "bad" centers, or the centers in your working layer...

with U2, you only have 3 centers in the same layer as your buffer, and it's easy to shoot to one of them: just a U, U' move (you just have to remember to undo it later)

with r2, you have more centers in your working layer...and it's kinda hard to shoot there...or isn't it?

I didn't try both methods a lot, but I think if I'll move away from commutators (not that I'm doing them for a long time...did just one real 4x4 bld try), it will be to U2


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## Stefan (Feb 7, 2008)

With oblique centers Lucas meant the new type of centers that the 6x6 has. Nice name, btw, had to look that word up in the dictionary.


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## Pedro (Feb 7, 2008)

oh, right...

well, I don't have a 6x6, so 

btw, is what I said correct? to "shoot" to other U centers I just do a  move and undo it at the end?


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## RobinBloehm (Feb 7, 2008)

Yeah, that works, but you have to make sure that have to do U' instead of U (for example) if you are at an odd position in the cycle, the same thing as in R2 or M2 or... bla


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## alexc (Feb 9, 2008)

I actually was just thinking about an alternative method to centers besides commutators a couple days ago. I thought about using U2 to solve one center at a time, but I didn't know it would actually work. That's why I didn't mention it on this forum. Nice job Stefan!


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## mrCage (Feb 12, 2008)

alexc said:


> I actually was just thinking about an alternative method to centers besides commutators a couple days ago. I thought about using U2 to solve one center at a time, but I didn't know it would actually work. That's why I didn't mention it on this forum. Nice job Stefan!


 
Hi 

I'd say the "U2" method is pretty much the same as doing commutator centers solving actually. Except leaving out the last turn in the commutator  The "U2" method would only work for centers first obviously - since it messes up edges and corners.

Btw, the method extends to higher order cubes right? And for that matter also "intends" to 5x5x5 and 4x4x4 would it not ?

- Per


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## Stefan (Feb 12, 2008)

mrCage said:


> The "U2" method would only work for centers first obviously - since it messes up edges and corners.


What? It doesn't mess up edges/corners. And if it did, why would that work for centers first, and why *only* for that? I'm completely stumped by that statement.

But while you're here... do you have a faster way for 3-cycling two opposite U centers and one D center (and doing an additional U2)? Here's what we got so far and I always thought about asking you because of your cage method:



RobinBloehm said:


> To shoot to Dbr I can use: (r F d2 F' r') U2 (r F d2 F' r')


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## Swordsman Kirby (Mar 1, 2008)

Huh, now that I actually bothered to read this topic, I realized that it was very very similar to my center 3-cycle approach. Basically, a three cycle would look like the following (after setup moves):

(r U2 r') u (r U2 r') u'

It's possible to use any face for setups. For U2 2-cycle you would get, for the same case:

u r' u' r U2 r' u r u' r' u r U2 r' u' r

Mine is shorter by half. Of course, there are other cases where mine is shorter by a smaller degree, but I think it's all about personal preference. I don't think you (Stefan) like doing three-cycle.


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## Lucas Garron (Mar 1, 2008)

Swordsman Kirby: Isn't that a way to just "freestyle" comms? I also use a few that way... 

Anyhow, I thought of this a while ago: Would R2 work as well for this? If someone tries it, could you also try R2?


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## ROOT (Mar 29, 2008)

howabout using ufL as a buffer and just adjusting the whole middle three layers so you can get UDFB. R will be a problem though. once your buffer is already solved, just do L/L'/L2 to adjust the buffer to a center that isnt solved. and once your done with that center do the same thing untill theyre all solved, then fix it with an L/L'/L2. i dunno


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## Lucas Garron (Mar 30, 2008)

ROOT said:


> howabout using ufL as a buffer and just adjusting the whole middle three layers so you can get UDFB. R will be a problem though. once your buffer is already solved, just do L/L'/L2 to adjust the buffer to a center that isnt solved. and once your done with that center do the same thing untill theyre all solved, then fix it with an L/L'/L2. i dunno


Actually, that's a good idea. I'd prefer Rub and R2, though.
The only issue I see with this is that visualization seems a bit more confusing right now.
I'll have to try this, though...


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## Stefan (Mar 30, 2008)

ROOT said:


> howabout using ufL as a buffer and just adjusting the whole middle three layers so you can get UDFB.


I don't understand.


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## mrCage (Mar 30, 2008)

Hi 

Sorry for ignoring this thread for such a long time. My forum search/contributions tend to be a bit random to put it mildly 

How about : (Ff) - [r' u' r,U] - (Ff)' ??? Yes a conjugate, so in some sense not a pure commutator. But good enough for me ;-)
Different cutplane versions is of course possible, for even larger cubes ...

- Per

(edit)

Another direct approach - though longer - would be:
[r' B' d2 B r,U*] U* = U/U2/U'

Note similarity with the following corner cycle:
[R' B' D2 B R,U*] 

(/edit)


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## KConny (Jul 23, 2008)

StefanPochmann said:


> Wait! I forgot why I forgot. Now I remember why I forgot: I didn't forget. Shooting from U to U is unnecessary. That's why I didn't cover it. I think. Maybe it is necessary. Or not? Once you have a U center in the buffer, you do just a U2 turn to break into the cycle starting at the target. Unless that one already contains a U center, too. In which case you can do a single U turn and start using the other two U center positions as buffer and target. I didn't fully think this through, though. Maybe that's the reason I didn't publish this method earlier. I'm confused now. Great.



I'm also confused, are you still confused? I've now failed about 6 attempts because of not really understanding how to handle shooting to U. Well, doing the actuall shooting is easy, but then reversing setup confuses me. Help? Anyone?


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## KConny (Sep 23, 2008)

Seriously, is there no one here who uses U2 that can tell me how to handle shooting to U?

Shooting to UFR is either U or U' depending on if it's in an odd or even place in the cycle, U layer might be good or bad, just as in M2, right? And when you're done with your cycle and need to go back to your original buffer are you then supposed to do U or U'? This makes me so confused, I thought I had it thinking that if you need to reverse the setup moves at the same status (odd or even) as you did the shooting it's just to reverse the U turn. Is this correctt?


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## shelley (Sep 23, 2008)

Starting new cycles from U centers always confused me the few times I tried U2 as well.

What if you just shoot from wherever the center is. E.g. you start a cycle from UFR, you shoot to UBL? It would eliminate a setup move at the beginning/end that I always seem to mess up.


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## mazei (Sep 23, 2008)

Err this might sound a little noobish but if any of you don't mind helping me, how do I apply the U2 method in a 4x4 BLD solve. I have a rough idea of how it works but the way I can think of takes too much to remember. So care to explain how you guys apply the U2 method. Perhaps this should be on another thread. Maybe you can send me an e-mail on the explanation. [email protected].

[Edit]
Never mind. I got it now. But just one question. What if your U centers are all done before you finish other centers? Do you just start a new cycle by just switching centers with an unsolved center? or do you turn the cube and start a new cycle on a new face?


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## KConny (Sep 24, 2008)

Start a new cycle by just switching centers with an unsolved center.


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## KConny (Oct 18, 2008)

So I think I've got this figured out, shooting to U centers that is. I made a little tabel of all the cases. 

SR | U | U' | U2
----------------
11 | U | U' | -
12 | U' | U | U2
21 | U | U' | -
22 | U' | U | U2

S=Shooting R=Reverse, U/U'/U2=setups
1=odd place in cycle, 2=even place in cycle.
So, if you shoot with U' at an even place in the cycle (2) and later need to reverse it at an odd place in the cycle (1) the reverse setup move should be U'. Yeah, hope you get it.


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## siva.shanmukh (Oct 20, 2008)

It was really hard memorizing the entire 4x4. But, I was finally able to finish my first 4x4 bld solve using 3OP for corners, r2 for edges and U2 for centers. U2 is actually very easy and efficient. I find it much easier to execute than using free style commutators as it is very easy to adapt to. I am not sure about how good I am at explaining but I will try to explain in the next post about how I did the U face(only if you want to know that is)


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## siva.shanmukh (Oct 20, 2008)

I dunno if this is the right thread to post this. But lemme jus do it and get corrected if I am wrong.

I tried to solve a 4x4 super-cube blindfolded once and got stuck with the parity case. No problems with edges. But the centers and corners were little problematic.

When I solved it, I was stuck at UBL and UBR swapped and ubl and ufr swapped. So I had to go ahead and solve it by doing the following from the current situation:


A UBR <-> UFL <-> UFR cycle
A ufr <-> ufl <-> ubr cycle
A ufr <-> ubl <-> ubr cycle
And solved the edges by shooting them in the following order
UFL -> URF -> UBR -> ULB
UFR -> URB -> UBL -> ULF
And a final U move.

Any idea of an easier way?


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## KConny (Oct 20, 2008)

Sure, do explain how you solve the U-centers.


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## siva.shanmukh (Oct 21, 2008)

KConny said:


> Sure, do explain how you solve the U-centers.



OK. I guess this is by default the same way anyone would solve it basing this concept. But anyway let me put it forward.

My buffer is ufr and I shoot it to ubl every time. My setups are pretty intutive and I don't think are worth posting it here.

I do all the thinking during memorization itself and there is only one action that I do that is shooting the ufr to the memorized location. I don't memorize it like breaking into a new cycle or finishing a cycle and stuff like that. 

My thought process for memo broken into steps for easy unerstanding:

Step1:

I start memorizing the sequence of locations as to where the ufr should go to and then where the next one should go to and so on. If I come across a U center some where for the first time, then I memorize it as ubl(move: U2).

Step 2:

If I come across the second white center in the sequence, then I memorize it as a ufl (move: U') if this is the odd position of the sequence or I memorize it as a ubr (move: U) if this is the even position of the sequence.
Now what ever was in ufl initially will come to buffer and I repeat Step1.

Step 3:

If we come across all the 4 U centers, this is when i break into new cycle. But I won't memorize it as a breaking into new cycle. I just memorize it as shooting it to some unsolved center and continue step 1 till I reach the same center again.

Step 4:
I actually manage to easily find that odd position or even position of the sequence by memorizing it in pairs. So if I my last one is not a pair, then I memorize it as an extra ubl and then an extra ubr/ufl(the compliment of the one that I memorized in the step 2)

Execution:
It is very straight forward now:
Just use setups to bring the center in the sequence perform a U2 and undo the setup. If it is one of the cases mentioned in step 2 or step 4, then the moves are as I mentioned there.

If my explanation is not clear enough, I can write an example solve.

I guess this can be used for 5x5/6x6/7x7 centers also. There will be exceptional situation in the case of 5x5/7x7 outer layer parity situation.

I am still expecting a reply for my post about the super cube BLD


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## KConny (Oct 21, 2008)

Well, you don't say anything about reversing the moves that you do in Step 2. Or do you solve centers last and just don't care if it's +2?


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## siva.shanmukh (Oct 21, 2008)

You missed it in. I did mention about that in my step 4


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## KConny (Oct 21, 2008)

But how do you figure out if you're supposed to memo ubr or ufl in step 4?


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## siva.shanmukh (Oct 21, 2008)

If you memorized ufl in the step 2, then you memorize a ubr in the step 4 and if you memorized ubr in step 2. then you memorize ufl in step4. Thats what I meant by saying compliment of the one that I memorized in step2



siva.shanmukh said:


> Step 4:
> I actually manage to easily find that odd position or even position of the sequence by memorizing it in pairs. So if I my last one is not a pair, then I memorize it as an extra ubl and then an extra ubr/ufl(the compliment of the one that I memorized in the step 2)


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## KConny (Oct 21, 2008)

Well that only works half of the time. What if you shoot to ufl (U') in step 2 the right reverse is not always ubl (U), it can also be ufl (U') depending on where in the cycle you did the shooting and the reversing.


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## siva.shanmukh (Oct 22, 2008)

siva.shanmukh said:


> Step 2:
> 
> If I come across the second white center in the sequence, then I memorize it as a ufl (move: U') if this is the odd position of the sequence or I memorize it as a ubr (move: U) if this is the even position of the sequence.
> Now what ever was in ufl initially will come to buffer and I repeat Step1.



In my second step, I never shoot a U center to ufl. Once I am done with 2 U centers on my sequence, it means I am done with ubl and ufr(buffer) Now I do a ufl/ubr and continue memorizing from the ufl center and it goes till I am done with the next 2 centers of U.

If you are mentioning about the odd/even position of executing U/U', then that case is take care by chosing the right one. I clearly mentioned that I do only a U' move if I am already done with even memorization and do only a U move if I am done with odd memorization. It means that I always will start with ufl center to memorize from then on.

If I didn't answer you properly, gimme a situation and I shall explain it.
Or you give an example scramble where you think my method doesn't work, we shall see if I have missed something somewhere. But as of now I don't see any flaw/lucky chance in how I solved it.


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## V-te (Dec 26, 2009)

Thank god I found this. 
I'm still a bit confused on the U2...can someone post an example solve?


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## Swordsman Kirby (Dec 26, 2009)

V-te said:


> Thank god I found this.
> I'm still a bit confused on the U2...can someone post an example solve?



This, to me, equates to "I like this method, but don't understand it at all." Do you know how to do M2 for 3x3x3 edges?


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## V-te (Dec 27, 2009)

Swordsman Kirby said:


> V-te said:
> 
> 
> > Thank god I found this.
> ...



No, I do not. Do I need to learn it to understand this?


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## xXzaKerXx (Dec 27, 2009)

lol nice new photo Stefan


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## V-te (Dec 27, 2009)

V-te said:


> Swordsman Kirby said:
> 
> 
> > V-te said:
> ...



So do I need to learn M2?


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## Chuck (Dec 27, 2009)

V-te said:


> I'm still a bit confused on the U2...can someone post an example solve?



Here, V-Te.
Example solve.


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## Sakarie (Dec 27, 2009)

V-te said:


> V-te said:
> 
> 
> > Swordsman Kirby said:
> ...



You do not have to, but it would have helped. 

But if you're going to do the easiest method for the edges of any >3 cube, it's m2. Learn it anyway, cause it's very good!


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