# Petrus Method



## Vryon (May 3, 2009)

Can you guys link me to Petrus Method ? Should i learn petrus method ?


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## akidnamedjack (May 3, 2009)

http://www.lar5.com/cube/


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## byu (May 3, 2009)

You have the link, and I say DO NOT learn petrus. Learn Roux instead. 
But that's just my opinion.


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## Nukoca (May 3, 2009)

You have the link, and I say DO NOT learn roux. Learn Petrus instead. 
But that's just my opinion.

Edit: Also check out CaptainCrash, he rocks. http://www.youtube.com/user/CaptianCrash44


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## daeyoungyoon (May 3, 2009)

Nukoca said:


> You have the link, and I say DO NOT learn roux. Learn Petrus instead.
> But that's just my opinion.
> 
> Edit: Also check out CaptainCrash, he rocks. http://www.youtube.com/user/CaptianCrash44



He speaks the truth.


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## Nukoca (May 3, 2009)

List of Petrus websites: (I'll keep adding on to this)

http://lar5.com/cube
http://www.petrus-speed.netne.net/1_3_The-Petrus-Method.html
http://www.wonderhowto.com/how-to-lars-petrus-method-for-solving-a-rubik-cube/
http://www.rubiksillusions.com/eng/rubiks_cube_solution_lars_petrus_method/1
http://www.howcast.com/videos/51995-The-Lars-Petrus-Method
http://www.truveo.com/The-Lars-Petrus-Method/id/4249747826
http://www.absoluteastronomy.com/topics/Lars_Petrus
http://howtosolvearubikscube.weebly.com/petrus-method-solution.html


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## daeyoungyoon (May 3, 2009)

If your going into Petrus just learn the method from http://lar5.com/cube then watch ErikJ's videos on youtube. After that, its just practice, practice, practice, practice..........And it sometimes help to rewatch some of ErikJ's videos after you get better because you will most likely understand it a lot better.


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## Gparker (May 3, 2009)

why did you make a thread about this. google is your best friend


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## byu (May 3, 2009)

Gparker said:


> why did you make a thread about this. google is your best friend



As I believe Shelley said:

There are no stupid questions, only people who don't use search and don't read around the forum a bit before hitting "New Thread"


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## Gparker (May 3, 2009)

byu said:


> Gparker said:
> 
> 
> > why did you make a thread about this. google is your best friend
> ...



exactly


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## Nukoca (May 3, 2009)

In the meantime, this can be the new cool thread to argue about whether Fridrich or Petrus is better!


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## byu (May 3, 2009)

Hey! What about Roux!


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## Nukoca (May 3, 2009)

byu said:


> Hey! What about Roux!



Petrus is better than Roux! (BTW I don't know anything about Roux)


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## byu (May 3, 2009)

Nukoca said:


> byu said:
> 
> 
> > Hey! What about Roux!
> ...



Roux is better than Petrus! (BTW I know a fair amount about Petrus)

REASONS TO BACK UP MY OPINION:
-Petrus has a really slow last layer system.
-Roux only requires knowledge of 9 full-length algorithms, and 3 really short 4 move ones. And if you want to be really lazy, I think you can get by with only 2 full length algorithms.
-Roux has 4 simple, fast steps. Petrus has 7 longer steps.
-Roux's last step is consisted of only <M, U> moves, allowing very fast moves.


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## Haste_cube (May 3, 2009)

byu said:


> Nukoca said:
> 
> 
> > byu said:
> ...



I agree with byu.
btw, I want to ask about something

I have seen the video of the roux method and CF
Aren't the last part of CF about places midges and the last part of roux or what are the same??


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## blah (May 3, 2009)

That last sentence of yours is completely incoherent but I think I get the point. Though I haven't seen it documented anywhere, I believe [the] Roux [method] was inspired by the last step of Waterman/CF (6E4C), and then he (Roux) sorta worked backwards to create a more economical beginning using blockbuilding. I think.


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## byu (May 3, 2009)

blah's explanation sounds reasonable.


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## Haste_cube (May 3, 2009)

uh... byu??
help me about the 3 step of roux
pretty please???


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## blah (May 3, 2009)

Haste_cube said:


> uh... byu??
> help me about the 3 step of roux
> pretty please???



That's the easiest step in case you haven't realized -.-


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## Johannes91 (May 3, 2009)

byu said:


> DO NOT learn petrus. Learn Roux instead.





Nukoca said:


> DO NOT learn roux. Learn Petrus instead.


Why do you guys think of methods as religions? Why can't he learn more than one? If you're so convinced that you're favourite method is the best, wouldn't he notice that by himself with time and choose to use it?



byu said:


> -Petrus has a really slow last layer system.


Lars himself has said that it's the F2L that's Petrus, you can solve LL as you wish. No need to use 3-look LL.



byu said:


> -Roux only requires knowledge of 9 full-length algorithms, and 3 really short 4 move ones. And if you want to be really lazy, I think you can get by with only 2 full length algorithms.


In what way is that better than Petrus?



byu said:


> -Roux has 4 simple, fast steps. Petrus has 7 longer steps.


Huh. The Petrus steps are much shorter, or if they aren't, you're doing something really stupid and shouldn't blame the method.



byu said:


> -Roux's last step is consisted of only <M, U> moves, allowing very fast moves.


And Petrus steps don't? S2 is often <U,F,R>, S3 consists of triggers, S4 can be just <U,R> and LL algs aren't bad, either.


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## ErikJ (May 3, 2009)

byu said:


> REASONS TO BACK UP MY OPINION:
> -Petrus has a really slow last layer system.
> -Roux only requires knowledge of 9 full-length algorithms, and 3 really short 4 move ones. And if you want to be really lazy, I think you can get by with only 2 full length algorithms.
> -Roux has 4 simple, fast steps. Petrus has 7 longer steps.
> -Roux's last step is consisted of only <M, U> moves, allowing very fast moves.



do some research. you obviously don't know what you are talking about.


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## Swordsman Kirby (May 3, 2009)

byu said:


> Roux is better than Petrus! (BTW *I know a fair amount about Petrus*)
> 
> REASONS TO BACK UP MY OPINION:
> -Petrus *has a really slow last layer system.*



I guess not.


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## spdcbr (May 3, 2009)

LEaRN FRIDRIcH!


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## JLarsen (May 3, 2009)

byu said:


> Nukoca said:
> 
> 
> > byu said:
> ...


-I don't get what is so slow about the ll system at all. Also as said before a method is not reliant on its last layer if it has an f2l. 

-So your actually trying to tell me that COLL or CMLL is 9 algs? You can solve petrus ll with 3 if you like. Sune, A perm, U Perm. 

-The steps to both methods, Roux in particular are not very simple. Roux makes noobs cry. 

-You reduce the cube you M U with Roux, RU with 
Petrus. 

-Just another point: I bet you aren't sub 1.5 with all your olls.


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## spdcbr (May 3, 2009)

Look's like fridrich and roux are the top speedcubing methods. Anyone want to take a poll?


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## byu (May 3, 2009)

spdcbr said:


> Look's like fridrich and roux are the top speedcubing methods. Anyone want to take a poll?



You're forgetting Petrus...

Ok, so apparantly I had no idea what I was talking about, so I'll have to find better reasons to back up Roux.


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## soccerking813 (May 3, 2009)

Sn3kyPandaMan said:


> -Just another point: I bet you aren't sub 1.5 with all your olls.



The Roux method doesn't use OLL, so why should he be?


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## Nukoca (May 3, 2009)

byu said:


> Roux is better than Petrus! (BTW I know a fair amount about Petrus)
> 
> -Petrus has a really slow last layer system.



There's the three-look last layer, which puts the corners in right permutation, then orients them, and then permutes the edges. If you want to get faster at LL, you either learn OLL and PLL or COLL. COLL is just as fast as the OLL/PLL alternative, and requires less algs. (OLL/PLL=57(?) and COLL= 40)



byu said:


> -Roux only requires knowledge of 9 full-length algorithms, and 3 really short 4 move ones. And if you want to be really lazy, I think you can get by with only 2 full length algorithms.



With Petrus, you can get by at a minimum of 4 algs. 2x2, 2x2x3, orienting edges, and the F2L are intuitive. The last layer requires Sune, AntiSune, Niklas, and then it's useful to know all 4 edge permutation algs, but you can get by on just knowing one, if you know what you're doing.



byu said:


> -Roux has 4 simple, fast steps. Petrus has 7 longer steps.


On the contrary. The 2x2 and 3x3 are lightning fast, as well as the edge orientation. The F2L is a little longer, but barely. The COLL/EPLL is just as long as any other alg, AND there's a much higher chance of getting to skip the last alg, which on OLL/PLL would be 1/57(?), but Petrus is 1/4.



byu said:


> -Roux's last step is consisted of only <M, U> moves, allowing very fast moves.



On average, how many moves does the last step take?

Anyway, as someone else already said, it's not like they're religions or something. It's all a matter of personal preference. YOU decide how fast the method you use is.


EDIT:


spdcbr said:


> Look's like fridrich and roux are the top speedcubing methods. Anyone want to take a poll?


There's already a thread about that. http://www.speedsolving.com/forum/showthread.php?t=10960


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## soccerking813 (May 3, 2009)

Neither Petrus or Roux have been mastered yet by many people, so it is impossible to say which method is better.


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## irontwig (May 3, 2009)

Swordsman Kirby said:


> byu said:
> 
> 
> > Roux is better than Petrus! (BTW *I know a fair amount about Petrus*)
> ...



This clever idea of his enables one to do LL stupid fast with 40 algs:

http://lar5.com/cube/270/index.html


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## Johannes91 (May 3, 2009)

byu said:


> Ok, so apparantly I had no idea what I was talking about, so I'll have to find better reasons to back up Roux.


So first you decide that Roux has to be the best method ever, and then you try to argue that you're right. That sounds really backwards to me. If it turns out you're not necessarily right, you could reconsider your assumptions instead of insisting that they're correct but you just don't know why.


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## Gparker (May 3, 2009)

Id say fridrich. Yes it's boring but quite fast.

Reasons:

1) F2L solved in 2 steps, Cross(or Ex cross) then corner-edge pairs, its very fast
2)Solve last layer with in only 2 steps if you know full.


Ok, thats not many reasons but there are cons to it to:

1) lots of algorithims
2) Hard to get really good at F2L
3) *BORING AND PLAIN* almost same thing every time

CFOP= 4 steps

and dont forget the fact that there are multiple algorithms for each case so you can choose one that is comfertable for you


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## JLarsen (May 3, 2009)

soccerking813 said:


> Sn3kyPandaMan said:
> 
> 
> > -Just another point: I bet you aren't sub 1.5 with all your olls.
> ...



Because he used fridrich for a long time fanboy.


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## JLarsen (May 3, 2009)

Gparker said:


> Id say fridrich. Yes it's boring but quite fast.
> 
> Reasons:
> 
> ...


I don't agree with the second con, but I agree with everything else. I'm sub 25 with Fridrich, and I've done maybe 50 solves with it total now.


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## soccerking813 (May 3, 2009)

Sn3kyPandaMan said:


> soccerking813 said:
> 
> 
> > Sn3kyPandaMan said:
> ...



I really hope that I heard that wrong and that you are not trying to insult me.


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## Gparker (May 3, 2009)

Sn3kyPandaMan said:


> Gparker said:
> 
> 
> > Id say fridrich. Yes it's boring but quite fast.
> ...




maybe, it depends if your a begginner or not, you understand the purpose of intuition and begginners don't. and yes, its not hard to get fast with fridrich, i think it is the fastest method theres going to be. until someone learns full zb.


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## soccerking813 (May 3, 2009)

Sooner or later someone is going to learn every alg for Fridrich, including OLL, PLL, F2L, and cross algs. Then everyone else is going to do the same thing, and it will be just firing off 7 algs in a row.


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## ErikJ (May 3, 2009)

soccerking813 said:


> Sooner or later someone is going to learn every alg for Fridrich, including OLL, PLL, F2L, and *cross algs*. Then everyone else is going to do the same thing, and it will be just firing off 7 algs in a row.



you should just stop talking now. no one anywhere will use algs for cross, ever.


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## irontwig (May 3, 2009)

soccerking813 said:


> Sooner or later someone is going to learn every alg for Fridrich, including OLL, PLL, F2L, and cross algs. Then everyone else is going to do the same thing, and it will be just firing off 7 algs in a row.



Cross algs are a waste. Since you already know what moves to do for the cross is already like an alg. It's better to spend time practicing xcross and/or 2x2x3, imho.


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## JLarsen (May 3, 2009)

soccerking813 said:


> Sn3kyPandaMan said:
> 
> 
> > soccerking813 said:
> ...



Nope. I was blatantly insulting you. And in case you missed the point of my argument, petrus has 7 oll's, and they're very fast.


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## Lord Voldemort (May 3, 2009)

ZZ ftw!
Though I actually use Fridrich, ZZ is just awesome.
The cube is reduced to <RUL> after EOline, which is amazing.
And blockbuilding is more efficient than F2L pairs, and lookahead isn't much harder than Fridrich look ahead. And like Petrus, you can have 2LLL in an easy 28 algorithms. Admittedly, getting good at EOline takes longer than cross proficiency or making a 2x2x2 block, but still.

Soccerking - I didn't recognize you without the green llama (?) thing in your avatar


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## waffle=ijm (May 3, 2009)

I like Roux 
But everyone knows that. 
I don't care about what method people use as long as they like it and like using it


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## ostracod (May 3, 2009)

This thread seems to have turned into a X METHOD IS THE BEST free-for-all.

...But anywayy,, I agree with Lord Voldemort. And I think that ZZ is in some ways easier to use than the Petrus method, because Petrus contains a lot of little steps which one must master (222 block, expand, bad edges, F2L, LL) whereas ZZ has fewer but larger steps (EOLine, 123 blocks, LL). With fewer steps, it is easier to master each one.


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## JLarsen (May 3, 2009)

In other words zz is easier.


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## EmersonHerrmann (May 3, 2009)

byu said:


> Nukoca said:
> 
> 
> > byu said:
> ...



Don't be so pompous. This is the last post I am making on this thread.


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## ostracod (May 3, 2009)

@SneakyPandaMan: Well, it seems to me that ZZ is easier. And it is easy in multiple ways!
- Not chopped up into many steps (as I said before; Fridrich has this benefit as well)
- Doesn't require lots of algorithms (Petrus style LL)
- Ergonomic, because of LUR group (Fridrich does not have this, Petrus puts the cube into RU group later in solve)

The down sides:
- EOLine and blockbuilding are more difficult to learn than cross and F2L pairs
- Eh... I can't think of much more. Move count is a little higher than Petrus?


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## Lord Voldemort (May 3, 2009)

Sn3kyPandaMan said:


> In other words zz is easier.



So? Is that a bad thing? (After EOLine, of course)
ZZ also has much look ahead after the first step, and it's all RUL turns. 
Note that after the 2x2x3 block/orient edges and EOline/1x2x3 block, Petrus and ZZ are the same. Optimally, ZZF2L is 25.5 turns on average, though optimality is difficult. Any stats of Fridrich/Petrus?

EDIT: @ Ostracod - Petrus only moves the F2L into RU, LL is still 3 gen.
One more thing: is the 6.1 average EOline for color neutral?


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## Escher (May 3, 2009)

ostracod said:


> @SneakyPandaMan: Well, it seems to me that ZZ is easier. And it is easy in multiple ways!
> - Not chopped up into many steps (as I said before; Fridrich has this benefit as well)
> - Doesn't require lots of algorithms (Petrus style LL)
> - Ergonomic, because of LUR group (Fridrich does not have this, Petrus puts the cube into RU group later in solve)
> ...



increasing the steps to a method =/= making the entire method more difficult/slower. Just look at Guimond vs Ortega for 2x2. And for many people, CLL can be slower than Ortega or Guimond, even though it only has 2 steps (make a layer, 1look LL) due to the difficulties of making an optimal (or near optimal) layer and recognition times.

Saying that 'one LL system requires less algs than another' I think is quite short sighted. You never get anything for free. 

I think the difficulty of going from nothing (noob) -> cross is not much harder than going from a good cross/2x2 block -> eoline, it just feels that way because we havent really struggled at a cube for a while. It's why ZZ is not a beginners method, at least in its most used incarnation. 

Anyway, I would like this thread to end, it is simply regurgitating old arguments. Find a method you like, and play with it. If you like it, great, if you dont, move on. There are enough around.


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## JLarsen (May 3, 2009)

Nah, not really. Just pointing it out. I was suggesting it took out the thought process to it, and made it more boring. Just my opinion.

Edit: this was to voldemort.


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## shoot1510 (May 4, 2009)

lol! Everyone complaining about which method is best. Why Roux? 4 step, last step M, U.
Erik use Fridrich and he beat the WR so.


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## byu (May 4, 2009)

Oh no, not the "The world record is with Fridrich" thing again. If we keep thinking that, speedcubing will never get better. Eventually, people will have mastered Fridrich and there will be no getting better.


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## waffle=ijm (May 4, 2009)

byu said:


> Oh no, not the "The world record is with Fridrich" thing again. If we keep thinking that, speedcubing will never get better. Eventually, people will have mastered Fridrich and there will be no getting better.



watch the first 20 seconds everything else is boring


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## Cride5 (May 4, 2009)

ostracod said:


> @SneakyPandaMan: Well, it seems to me that ZZ is easier. And it is easy in multiple ways!
> - Not chopped up into many steps (as I said before; Fridrich has this benefit as well)
> - Doesn't require lots of algorithms (Petrus style LL)
> - Ergonomic, because of LUR group (Fridrich does not have this, Petrus puts the cube into RU group later in solve)
> ...



I've posted this elsewhere, but thought I'd repeat my list of ZZ benefits for the non-believers 


 R U L face turns improve F2L ergonomics
 No cube rotations improves ergonomics
 Oriented edges improves F2L lookahead
 Initial EOLine phase makes better use of inspection time (compared with Fridrich cross)
 Automatic orientation of U-Face edges means:
 Fewer OLL algs required for OLL/PLL (comparing with Fridrich)
 More options for LL including COLL/EPLL, WV etc
 Not impossible to achieve 1LLL (although difficult)

When doing FM solves, in the back of your mind you're always thinking about move efficiency - ie: how much closer does each move take you to your goal. I believe the moves made during EOLine do a lot more to help the rest of the solve than the equivalent number of moves used during the Fridrich cross. EO helps you during F2L, with move ergonomics and lookahead. It also helps you on LL by pre-orientation of the LL edges, leading to easier/more efficient LL options.

It seems that ZZ should be better than Fridrich _in theory_, but we've yet to see that proved in practice. All the more reason to learn it, and learn it good


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## Escher (May 4, 2009)

Cride5 said:


> - Initial EOLine phase makes better use of inspection time (compared with Fridrich cross)



Elaborate please, I don't think we have the same definition of 'better'...


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## Lord Voldemort (May 4, 2009)

Sn3kyPandaMan said:


> Nah, not really. Just pointing it out. I was suggesting it took out the thought process to it, and made it more boring. Just my opinion.
> 
> Edit: this was to voldemort.



With all due respect, have you ever tried ZZ?
EOline takes more thought process than building a 2x2x2 block. Extending the 2x2x2 block with a 2x2x1 block is what you do in ZZ as well, except you're adding to a line. 



Escher said:


> Elaborate please, I don't think we have the same definition of 'better'...



Well, in Fridrich, all you do is place 4 edges. In ZZ, you Place two edges. However, you also orient all edges, which allows you to solve the F2L (and the LL, if you want), in only the subset <RUL>. It orients the LL edges once you get there, which mean a faster OLL if you choose to use it, since Sune, Anti-Sune, and Double-Sune cases come up more often than not. It brings up the option to use things like ZZ-b, a 1LLL in 170ish algorithms which could potentially be very fast. 170 is a big number, but compare it to the 800 you need for ZBLL with Fridrich, and you see which is easier. Final note: EOLine takes 6.1 turns on average, while Cross take 5.8, so it's not like you're taking 20 turns on the first step or something.

ZZ F2L is optimal 26 turns, and the turns are free of cube rotations or F/B turns. For Fridrich, I think it's around 28 for F2L. Also note that in ZZ you have the LL edges already oriented, so an added benefit outside of F2L.

The reason ZZ has no well-known fast users (like Erik Johnson for Petrus and everyone else for Fridrich) is that so few people know about it. The first (useful) document I've seen on it in English was published on 8/13/08, which isn't too long ago compared to the decades Fridrich has.


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## Cride5 (May 4, 2009)

Lord Voldemort said:


> Sn3kyPandaMan said:
> 
> 
> > Nah, not really. Just pointing it out. I was suggesting it took out the thought process to it, and made it more boring. Just my opinion.
> ...



Well elaborated voldemort, couldn't have put it better myself


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## Lord Voldemort (May 4, 2009)

Thanks 
What LL steps do you use for ZZ?


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## Cride5 (May 4, 2009)

Just OLL/PLL, so two looks. Too busy to learn other options ATM, plus I really need to get some practice on F2L. I'm still V sloooow


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## Johannes91 (May 4, 2009)

Lord Voldemort said:


> Well, in Fridrich, all you do is place 4 edges.


It's not like you're not allowed to plan more than that. Many of the fast cubers look for the first ce-pair, too.



Lord Voldemort said:


> <RUL>


<R,U,L>



Lord Voldemort said:


> ... the 800 you need for ZBLL with Fridrich


How did you calculate this? Anyway it's not ZBLL, I don't know if there's a name for it; usually it's called just 1-look LL.



Lord Voldemort said:


> Final note: EOLine actually needs _less_ turns on average than a cross


How did you measure this?



Lord Voldemort said:


> ZZ F2L is optimal 26 turns ... For Fridrich, I think it's around 28 for F2L.


Would be a good idea to cite where these numbers are coming from. Solving the whole F2L step in one go optimally? Probably not, so how is it divided to sub-steps and how they are solved, etc.. I don't know how ZZ solvers do it.

The 4 ce-pairs in Fridrich can be solved in about 23 moves, see Stefan's Hume.


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## Lord Voldemort (May 4, 2009)

You seem to understand EOline better than I do though.
I've mostly been working on my blockbuilding, and since I usually do ZZ for OH only (I have to get sub-20 on Fridrich before I switch ), so I have plenty of time to look ahead and make better blocks.


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## shoot1510 (May 4, 2009)

waffle=ijm said:


> byu said:
> 
> 
> > Oh no, not the "The world record is with Fridrich" thing again. If we keep thinking that, speedcubing will never get better. Eventually, people will have mastered Fridrich and there will be no getting better.
> ...



I'm gettin a pain in the neck learning all F2L cases, Full OLL and PLL.

How does a kid or a person start cubing with Fridrich.
1. Kid buy a official Rubik's cube and read the instructions how to solve the Rubik cube. (LBL-Similar to Fridrich)
2. Then he/she want to get faster by going to google and search how to get faster at Rubik cube and learn more algs. (keyhole method, F2l, zz, oll, pll, finger tricks)
3. As time goes on, the kid will later on master the Fridrich method.


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## Lord Voldemort (May 4, 2009)

Johannes91 said:


> Lord Voldemort said:
> 
> 
> > Well, in Fridrich, all you do is place 4 edges.
> ...



In order of quotes

1. I didn't account for that, I suppose. However, it could be done with ZZ as well.
2. I shall remember commas for the future.
3. I might be confused, but to get a 1LLL with pure Fridrich, the most well known way (or so I thought) was ZBLL. ZBLL uses 500 for 1LLL and then another 300 to orient edges while simultaneously forming and inserting the last F2L pair. Could someone correct/affirm me on this?
4. The place where I found it cited this for the cross.
this is the page for EOline.
I see now that I was comparing QTM for cross with HTM for EOline, my apologies for the misinformation. I'll edit the post.
5. I was also citing the same study. For what he calls "greedy optimality", F2L would take 23+6=29, as I was including Cross in the F2L. I have already showed you my source for EOline, and here's the post talking about ZZ blocks (I think you'll find the source trusworthy, considering it is from you )

Anything I missed?


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## Cride5 (May 4, 2009)

Johannes91 said:


> Lord Voldemort said:
> 
> 
> > ZZ F2L is optimal 26 turns ... For Fridrich, I think it's around 28 for F2L.
> ...



I'm not sure if this is the 'proper' ZZ way to do it, but I solve the L & R 1x2x3 blocks in four stages. Two 1x2x2 blocks, and two 1x1x2 blocks. The order depends on the situation, but a 2x2 always comes before its connecting 1x2. I have no optimal figures for this strategy, but after an average of 10 solves I got 27.0 (not including EOLine). I'm sure the optimal figures would be much less, especially if each side was solved as one. 

Johannes, where did you get the code for your online solver? I wouldn't mind compiling a few stats


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## Lord Voldemort (May 4, 2009)

See my reply, it's the link before the


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## Cride5 (May 4, 2009)

Thx... so that gives 19.7176 moves for doing each side as one. I wonder why I'm using so many moves :confused: It would be interesting to see the optimal stats for the 4-stage strategy, but it might prove difficult to specify programatically since block selection depends on the situation.


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## Lord Voldemort (May 4, 2009)

Optimality is HARD...
You have to blockbuild while setting up the next block.


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## Johannes91 (May 4, 2009)

Lord Voldemort said:


> 3. I might be confused, but to get a 1LLL with pure Fridrich, the most well known way (or so I thought) was ZBLL. ZBLL uses 500 for 1LLL and then another 300 to orient edges while simultaneously forming and inserting the last F2L pair. Could someone correct/affirm me on this?


That method is called ZB. It's just like Fridrich, but instead of solving the last pair normally, LL edges are oriented at the same time (a.k.a. ZBF2L). Then the LL is the same as in Petrus and ZZ, and doing it in 1 look is called ZBLL. It requires 177 unique algs or 271 with inverses counted separately or 494 with mirrors counted separately, too.

So 493 + whatever ZBF2L needs is around 800. I thought you meant doing the Fridrich LL in one look without modifying F2L, which needs more than that (1212 or 2054 or something else).



Lord Voldemort said:


> 5. I was also citing the same study. For what he calls "greedy optimality", F2L would take 23+6=29, as I was including Cross in the F2L.


Oh, ok. I blame the cubers who don't include it for confusing me.

The steps I used in the ZZ numbers are significantly longer than the ones in Fridrich F2L, so I'm not sure how meaningful comparing the numbers is.



Lord Voldemort said:


> Anything I missed?


Nope, thanks.



Cride5 said:


> Johannes, where did you get the code for your online solver? I wouldn't mind compiling a few stats


I wrote it, but most ideas are from Jaap's and Kociemba's sites. If the stats you're thinking of are similar to the solvers on that page (not something like solve a 4x4x4 maze cube optimally), just let me know and I'll generate them.


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## Nukoca (May 4, 2009)

Are there algs written out for something like EJF2L, but for COLL? So you can have a corner unoriented in the F2L and get it fixed during the COLL?


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## Cride5 (May 4, 2009)

Johannes91 said:


> Cride5 said:
> 
> 
> > Johannes, where did you get the code for your online solver? I wouldn't mind compiling a few stats
> ...



... OK this is a big ask, so no worries if you don't have time! On the ZZ 1x2x3 page would it be possible to include options for breaking it down into 1x2x2 + 1x1x2 blocks. As a ZZ cuber it would be very nice to be able to compare my blockbuilding with the optimal solutions.

Optimal blockbuilding in four stages is certainly a realistic prospect for speedsolvers so the stats for this would hopefully provide a realistic comparison to Fridrich F2L.

... apologies Petrus users, we seem to have veered wildly off-topic


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## Vryon (May 4, 2009)

Alright, "Petrus" and "Roux" is the same. You still can solve the 3x3x3 rubiks cube with both ways. >__>


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## Lord Voldemort (May 4, 2009)

Johannes91 said:


> The steps I used in the ZZ numbers are significantly longer than the ones in Fridrich F2L, so I'm not sure how meaningful comparing the numbers is.



Could you elaborate?
I don't understand what you mean by steps.
Are you talking about the furthest number of turns it looks ahead to find a solution?
One more question: is Hume finished/released yet?
It sounds like a useful piece of software.


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## brunson (May 4, 2009)

Lord Voldemort said:


> 5. I was also citing the same study. For what he calls "greedy optimality", F2L would take 23+6=29, as I was including Cross in the F2L.



Don't use the abbreviation F2L for that. F2L has a very specific meaning in the context of CFOP. Use either "Cross+F2L" if you mean cross plus Fridrich F2L or "first two layers" for anything else.


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## Nukoca (May 4, 2009)

Can we move this discussion to a different thread? When people click on this thread, they expect to read a discussion about Petrus, not ZZ or ZB!


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## Cubemaster37 (May 4, 2009)

I understood the Petrus Method but which Algorithms you are using to finish the last layer so fast?


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## soccerking813 (May 4, 2009)

Most people use corner OLL and then PLL I think. Or COLL and EPLL.


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## JLarsen (May 4, 2009)

I use oll pll. Those oll's are so fast, and pll is decent as well.


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## James Kobel (May 4, 2009)

You are all wrong, and frankly you are all being idiots. The term "best" is completely opinion, and no one's opinion is right. If you were going for something like which method is fastest, that would be fine, but this has no fact involved. You can't shange someone's opinion without fact, and the only facts you are bringing up are really just opinions, such as "Petrus last layer is harder" or something like that, it all depends on who you are and what you use. So shut up.


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## shoot1510 (May 4, 2009)

James Kobel said:


> You are all wrong, and frankly you are all being idiots. The term "best" is completely opinion, and no one's opinion is right. If you were going for something like which method is fastest, that would be fine, but this has no fact involved. You can't shange someone's opinion without fact, and the only facts you are bringing up are really just opinions, such as "Petrus last layer is harder" or something like that, it all depends on who you are and what you use. So shut up.



For example: If Gives you hell is the top #1 song at MTV, it their opinion only.


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## Lord Voldemort (May 4, 2009)

brunson said:


> Lord Voldemort said:
> 
> 
> > 5. I was also citing the same study. For what he calls "greedy optimality", F2L would take 23+6=29, as I was including Cross in the F2L.
> ...



Can't it also mean first two layers though?
I realize that it's a step in Fridrich, but most people I've seen use it describe first two layers.


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## MistArts (May 5, 2009)

Cride5 said:


> When doing FM solves, in the back of your mind you're always thinking about move efficiency - ie: how much closer does each move take you to your goal. I believe the moves made during EOLine do a lot more to help the rest of the solve than the equivalent number of moves used during the Fridrich cross. EO helps you during F2L, with move ergonomics and lookahead. It also helps you on LL by pre-orientation of the LL edges, leading to easier/more efficient LL options.
> 
> It seems that ZZ should be better than Fridrich _in theory_, but we've yet to see that proved in practice. All the more reason to learn it, and learn it good



In FM, you try to orient pieces independently. Your moves should solve a section of a cube. Orientation doesn't solve a piece, unless it's already permutated, and you usually don't "pure" orient pieces. What you should do in FM is to permute in the correct orientation from any starting orientation. So with ZZ, it doesn't help your moves, it *restricts* them. I'm not saying Fridrich is better at FM. It has restrictions too. Freestyle block-building gives less restrictions to these 'methods'. Of course, FM is different than speed.


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## ostracod (May 5, 2009)

I agree with MistArts, and that is why I said a couple days ago in this thread that the downside to the ZZ method is a slightly higher move count than Petrus; this is because ZZ restricts the cube group earlier than Petrus.

(and to correct an error in my earlier post, Petrus does NOT put the whole cube into the RU group after the bad edges step; it merely makes the F2L solvable with only RU. Otherwise you'd have something like ZZ-d on your hands, and we know that's almost impossible. ;D)


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## Cride5 (May 6, 2009)

MistArts said:


> Cride5 said:
> 
> 
> > When doing FM solves, in the back of your mind you're always thinking about move efficiency - ie: how much closer does each move take you to your goal. I believe the moves made during EOLine do a lot more to help the rest of the solve than the equivalent number of moves used during the Fridrich cross. EO helps you during F2L, with move ergonomics and lookahead. It also helps you on LL by pre-orientation of the LL edges, leading to easier/more efficient LL options.
> ...


I wasn't suggesting that you should use EO in FM solves, I was just hi-lighting the principal of move efficiency. Although orientation doesn't solve a piece, it does bring it closer to its goal state. You are correct that both edge orientation and the cross introduce restrictions, but I question whether the restrictions introduced by EOLine are worse than the restrictions introduced by the Cross. Although I don't have comprehensive statistics on this, I'm inclined to believe that the restrictions introduced by EOLine have a less significant effect on move count. 

The following stats show the optimal move-count of a colour neutral cross and a colour neutral EOLine, followed by the number of moves required to complete the cube using the Kociemba algorithm. It suggests that although EOLine has a slightly higher move count, it results in a lower move-count for completion of the cube.

Compiled using http://laire.dy.fi/jarcs/

Cross | EOLine | Scramble
-------+--------+----------
4 + 24 | 5 + 20 | U' B' D L2 D R' L2 U R F2 U L' B2 L F2 D2 B F2 R F L' F L' R' B2 
5 + 23 | 5 + 21 | U B2 R2 D' R2 U' L2 F R2 B2 D2 L2 F' R' L B D' U' F' D' B2 F L2 R B
5 + 19 | 4 + 20 | F L2 R' F R B L F' B2 U2 R' L2 D' R2 B2 R' L B2 U F L' F' L U R2
5 + 23 | 5 + 18 | D' U' L F2 L F' D2 F2 U' R2 U R' D' R' U D' L2 B2 U F2 B' U B D2 L
3 + 21 | 5 + 21 | R F' L' F' U' D L R2 B2 R' B2 U2 D2 B2 L2 D2 B' R' D' R2 D2 L' U R B
4 + 23 | 4 + 22 | D' L' D' L2 R2 D B R2 D2 B2 D' U' B F2 R2 F' D' B2 L' U R2 D' B' F D
5 + 20 | 5 + 20 | B' L2 D R' L2 F2 R F' R F' U2 F2 R' L' D' B' R' B2 U' B' D' B2 L2 F2 R2
4 + 21 | 4 + 20 | L2 R2 B2 R F R2 B U2 L2 F D' L2 U2 F2 R' B R B' R2 L2 U2 R2 D2 R' L2
3 + 21 | 4 + 19 | D2 U' R U' R2 U2 L2 U B' U2 F2 D' B' L B2 F2 U' B' U2 B' R' B D R2 F2
5 + 24 | 4 + 20 | R2 D F2 R L' B' D' B2 R' L2 F B2 U F' B2 R' U' F D R D2 L U B' R

Avg for Cross = 4.3 + 21.9 = 26.2
Avg for EOLine = 4.5 + 20.1 = 24.6

I'm not calling this proof because only 10 runs were used, and use of the Kociemba algorithm may introduce bias towards pre-orientation of edges. It would however be nice to get some hard statistics on this!



ostracod said:


> I agree with MistArts, and that is why I said a couple days ago in this thread that the downside to the ZZ method is a slightly higher move count than Petrus; this is because ZZ restricts the cube group earlier than Petrus.



With Petrus a good solver can complete F2L with less moves then Fridrich/ZZ F2L, but this requires a lot of mental effort to do. In a speedsolving context it would be more useful to compare the average move count of a Petrus speed-solver, than the optimal move count. With both Fridrich and ZZ it is plausible for a speedsolver to consistently achieve an optimal move-count for each stage, but I'm not sure if the same can be said for Petrus.

... actually, does anyone know whether optimal petrus + EO is less moves than optimal EOLine + 1x2x3 + 1x2x3??


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