M2M Day 63: How to solve a Rubik’s Cube
This post is part of Month to Master, a 12-month accelerated learning project. For January, my goal is to solve a Rubik’s Cube in under 20 seconds.
Over the next few days, I’ll be experimenting with a number of training techniques and exercises, to determine the best 30-day Rubik’s Cube training program. In particular, the program needs to get my Rubik’s Cube solving speed consistently under 20 seconds.
To understand my training program and the rest of this month’s posts, it’s important that you first understand the method I use to solve a Rubik’s Cube, which is called CFOP.
Intro to CFOP
CFOP is the most common speed cubing method and is the one that I originally learned.
CFOP stands for 1. Cross, 2. F2L, 3. OLL, 4. PLL, which are the four steps used, in this method, to solve the cube. These acronyms probably don’t mean much, so let me go through each one.
1. Cross
With a fully scrambled cube, I start by finding the white center, which identifies the white side of a solved cube.
I then find the white edge pieces, and move them into place, so that a white cross is formed on the white side.
It’s important that the edge pieces not only match up with the white center, but that they also match up with the correct color of the adjacent centers.
For example, the white and green edge piece should be placed between the white center and the green center. The white and red edge piece should be placed between the white center and the red center. And so on.
The cross is complete.
2. F2L (First 2 Layers)
Once the cross is formed, I put the white side of the cube on the bottom, which looks like this.
In this next step, F2L, or ‘First 2 Layers’, I’m focused on solving the first two layers of the cube, starting from the bottom.
Since the center pieces and ‘white + color’ edge pieces are already solved (from the last step), I only need to focus on solving the highlighted areas below.
After placing the correct pieces in these slots, the cube looks like this.
Here, in the solved state, it’s easier to visualize which pieces I moved during F2L: I positioned the four edge pieces (like the blue and red edge piece) between the corresponding centers (like the blue center and the red center). I also positioned the four corner pieces that have a white side and two other colored sides (like the white, blue, and red corner piece) in the correct slot on the bottom layer.
As a result, when I finish F2L, the white side is completely solved.
F2L is complete.
3. OLL (Orient the Last Layer)
At this point, the white side is completely solved and the first two layers of the cube (from the bottom) are solved. Thus, I only need to solve the last layer of the cube.
To do this, I break down the last layer into two parts. First, in this step, OLL, I solve the yellow side, which is also known as orienting the last layer.
At this point, on the yellow face, it’s possible for the yellow pieces to be configured in 57 different ways.
The fastest speed cubers have memorized the 57 different algorithms necessary to most efficiently solve the 57 different configurations (one algorithm for each configuration).
However, if you’re willing to give up efficiency, it’s possible to solve the yellow side with far fewer algorithms. I currently only know 9 of the algorithms, which means I’m highly inefficient at this step.
Upon completing the necessary algorithm, the yellow side is solved.
OLL is complete.
4. PLL (Permute the Last Layer)
After finishing OLL, the cube looks like this.
The first two layers and the yellow side are solved. The only thing left to solve, during this step, PLL, is the rim of the last layer, which is also know as permuting the last layer.
There are 21 different configurations for PLL, which can be solved most efficiently with the corresponding 21 algorithms.
I currently know 7 of the PLL algorithms, which is enough to complete PLL in twice as many moves as a competitive speed cuber.
After executing the appropriate PLL algorithm, the rim of the last layer is solved.
And as a result, the entire cube is solved.
Read the next post. Read the previous post.
