Yet another talk about Rubik's Cube

After talking about the LBL Beginner Method and the Fridrich Method,
it's time to talk about the new advance method that I just manage to fully understand two weeks ago, The Petrus Method.

Basically, I think that this method is quite interesting as it is really based on a strong understanding on Rubik's, which mean you will have more free moves to make than the LBL method.


As previous posts, I won't really go deep into it, will just give a brief explain on the concept of this method.

First, a well scrambled cube.


Then, form a 2x2x2 block on wherever you like.


Expand it to 2x2x3.


Flip it 180 degree, proceed with fixing the edges.


First 2 layer.


Position corners.


Flipping corners.


Permuting edges, and it's completed!



Well, I think there are only 3 basic algorithms used in this method, and they have names, which are Niklas (Positioning corners), Sune (Flipping corners), and Allan (Permuting edges).

Another interesting thing about Petrus is, all of the algorithms have their own names.
So when you are discussing with your friend, instead of saying o21, n17 of Fridrich, you can just speak their names out, as if you both are talking about another friend of yours.


Step one, forming a 2x2x2 block.
It is actually quite an easy thing to do, 'cause there is not many restriction, you can move freely in most directions, but in order to get a good time, this step must be done within 5 seconds, which I am still quite poor on it.

Step two, expand to 2x2x3.
When you are at the end of completing first step, you should determine which side you wanna expand your block at, and this needs a good observation.

Step three, fixing bad edges.
This is a bit tricky for most people, I think I was stuck at this step also. Anyway, it is not really hard, maybe I wasn't paying full effort on understanding it. With the wrong orientation, of course it is a bad edge, the photo above shows all the edges are correctly flipped. One add on, bad edges come in pair.

Step four, first 2 layer.
It is having almost the same concept as Fridrich F2L, but with restriction of only R and U faces can be turned, in order to not to mess up the orientation of the edges. This step can be a bit annoying if you can't get it right.

Step five, positioning corners.
One thing good about Petrus is that after finishing two layers, a cross is automatically formed at the top layer, cutting down one step of flipping edges. This is the consequence from step three. So, we straight proceed to positioning the corners to the right place. Niklas is the algorithm to swap 2 adjacent corners. A 7-step-algorithm, not really hard to remember.

Step six, flipping corners.
There are actually 7 cases after the corners are positioned correctly. But by performing Sune, or Sunes, all the cases can be easily solved, and we are done with the orientation of last layer.

Step seven, permuting edges.
With the corners are permuted and orientated correctly, we are left with swapping edges. There are 4 cases: clockwise swapping, counterclockwise, cross, zig-zag. With Allan, all the edges will be placed correctly.


Petrus solving

I have a bad time using this method.

Fridrich

I will still stick to this, which is actually quite interesting also, especially the second step.



Well, that's it, the Petrus Method,
As you all can see from the video, I am really not that good in Petrus, because this method needs a good observation, and the method of observing is quite different from what I've been using for 5 months.
So, Petrus Method is just for fun, won't really train on it.