## U Perms (Revisited)

Slow-Motion videos of these algorithms are available here.

U Perms. Round 3. I sort of accidentally learned the U Perm (edge cycling) through the Beginner’s Method and its clunky final algorithm: F2 U(’) R’ L F2 R L’ U(’) F2. Then I started learning PLLs and wrote about the more efficient approaches I had found (now-stricken in the table below). When I did my foozled PLL time attack, that Ua was my fastest with Ub second. But those still involved a lot of moves, and Ub had a sort of clunky flow.

When I learned double M flicks, I started doing Ua with the new M/U algorithm. But I couldn’t get Ub figured out, with my hands mis-positioned for the U’ turns. Then I stumbled onto Anotine Cantin’s video on how to fingertrick Ub. A little awkward at first with the right index finger pulling left to right for U’, but it wound up being pretty easy after a little practice. Here’s my video showing both:

Once I got the finger-tricks figured out, these wound up having a really nice flow. And, in contrast to the older versions, there’s an elegant symmetry to the clockwise and counter-clockwise algorithms.

U PERM (Edge Cycle)

# Ub PLLClockwise

## M2 U’ M U2 M’ U’ M2

Onward….

### 10 thoughts on “U Perms (Revisited)”

1. Russ February 11, 2018 / 10:04 am

The algorithms shown under the cube images are wrong. If you follow them with the cube arranged as in the image, you scramble it further into a z-perm situation.

Ua should be: M2 U M’ U2 M U M2
Ub should be: M2 U’ M’ U2 M U’ M2

• Adventures in Cubing February 11, 2018 / 5:42 pm

Hello. Thanks for the comment. I think that’s what I have for the algs, no? I’m not sure if the images were rendering properly for you. I had to correct something in the code just now. This seems good now.

2. Russ February 11, 2018 / 5:47 pm

The third move in each algorithm should be M’, not M. And the fifth move in each algorithm should be M, not M’.

I found this page using a Google search, and despite the problem with notation, I did learn something useful from it. It just took a few minutes to figure out why the algorithms weren’t working for me. Thanks —

• Adventures in Cubing February 11, 2018 / 7:56 pm

Hmmmm. I’m not sure I agree. The M2s don’t matter; M2 or M’2 are effectively the same. (I typically do M’2, despite my notation.)

The third move — which I notated as M — moves the U layer into the F layer — just like an R’ or an L. M slice follows the same notation format (for clockwise vs. counter-clockwise) as L. So, that should be an M.

Check out my slomo video of these perms: https://adventuresincubing.com/2014/10/09/slomo-u-perms/

Does that clear things up?

• Russ February 11, 2018 / 10:23 pm

I had already watched the videos, and I follow what you’re saying now. But the videos somewhat contributed to my confusion. They show how to finger-trick these algorithms, and the move notated as M is executed in the opposite direction as the move notated as M2 (in the video). I had also read somebody else’s page, which talks about the same algorithms but notates them the way I suggested, here: http://thetelecubievison.tumblr.com/post/54944215777/u-perms-right-hand-or-middle-slice. When yours weren’t working right for me, the ones on the other page worked.

So either that other page notates the algorithms as I thought, or they do it the same as you but start with the cube turned 180 degrees compared with your diagrams.

• Adventures in Cubing March 9, 2018 / 8:23 am

I think your confusion is in the orientation of the U layer. My algs are based on the “bar” (the same colored corner-edge-corner trio) pointing away and in the B layer. The algs in the doc you referenced are designed for the bar being in the F layer pointing forward. It’s great to learn both, but it’s also sometimes hard to keep straight all of these very similar algs. So, I just AUF to put the bar in the back (vs. AUF’ing to put it in the front).

Let me know if this explanation helps….

3. Russ March 9, 2018 / 8:43 pm

This is probably more detail than you bargained for, but with the advantage of hindsight, I can explain exactly how the misunderstanding came about. Please bear with me — this will all make sense.

When I execute an R move, I use the fingers on my right hand to turn the R face clockwise. Prior to learning these alternate U perms, I almost always executed my M slice moves with fingers on my right hand. So I had that influencing me to think of M slice moves as being notated like the R face, rather than the L face.

But there’s more: When notating moves that turn two layers at once, lower-case letters are used. What’s an r move? It’s the one that turns the R and M slices together in a clockwise direction with the right hand. The move that turns the R and M slices together in a counter-clockwise direction is notated r’.

So all of my previous experience told me the third move in your video was M’, not M. Reinforcing my misunderstanding was that even though it’s executed in the opposite direction of the first move, both are notated without the prime mark (‘). So it looked like the third move in your notation was wrong — in my head, that was clearly an M’ move, not M.

I am no longer confused. I understand that the M slice is notated like the L face, not the R face. Your notation is correct, even if it didn’t make sense to me at first. And I’m using these algorithms without problem in my solves now. Thanks again —

• Adventures in Cubing March 12, 2018 / 8:10 am

Hi, Russ. “More detail than I bargained for”? I mean, I created a blog to chronicle my “journey.” Details are what it’s all about! Thanks for taking the time to ask questions and follow up. Happy cubing!