Rubik's Cube: origin, how to solve it, records…

Origin of the Rubik’s Cube

The most famous puzzle in the world was designed by Ernő Rubik , a Hungarian professor of architecture in the year 1974 . It was licensed to the Ideal Toy Company and in 1980 it had such a boom that it was considered Best Game of the Year . The cube was born as an experiment by Ernő for his students to understand structural problems in three-dimensional objects. However, by shuffling the cube, he realized that he had inadvertently invented a puzzle .

Its beginnings were not easy. Because of the laws of Hungary, Rubik was on the verge of not being able to patent the toy. Later, he was sued by Larry Nichols, who years before had created a similar puzzle, but 2x2x2, in Canada. On the other hand, and almost at the same time, an engineer in Tokyo created a very similar game, considering it an independent reinvention.

Parts, movements and notation in the Rubik’s Cube

When we refer to the Rubik’s Cube, we are talking about a 6-sided cube and a 3x3x3 matrix . The colors of the faces are indifferent, although it usually begins to be resolved by the white face.

The cube can be divided into the following parts :

• Center : It is the only piece that cannot be moved from the cube. There are 6 in total.
• Edges : share two colors. There are 12 in all.
• Vertices : they are made up of three colors. There are 8 in all.

There are also other cubes that differ from the original Rubik’s, but have the same name. They are the following:

• 2x2x2: It has no center and no edges. It can be solved as 3x3x3 by imagining the color of the faces and applying the algorithms that serve to move vertices.
• 4x4x4 : The center is made up of four pieces and each edge is made up of two pieces.
• 5x5x5 : The center is made up of nine pieces and each edge is made up of three pieces.

In most of these cubes, the method is usually to transform the puzzle into something similar to a 3x3x3 and solve with a method for one of these cubes. However, in some cases specific parity problems may appear, which must be solved with very specific algorithms, specific to each cube model in question.

Terminology

Rubik’s Cube has its own notation . To do this, it is always considered that we have the cube in front of us, and the parts are named as follows:

• F : front layer
• L : left layer
• R : right layer
• U : upper layer
• B : back layer
• D : lower layer

When the movement is clockwise, the movement is written with a single letter. When the movement is going to be carried out in the opposite direction, it is written with an apostrophe. In the same way, if the letter is followed by a 2, 2 moves will be made in a row:

• F : movement of the frontal layer in a clockwise direction
• F’ : counterclockwise movement of the front layer
• F2 : double movement of the front layer in a clockwise direction

However, each method of solving the cube can be accompanied by its own notation.

How to solve the Rubik’s Cube

There are several methods to solve the Rubik’s Cube. If you’re just looking to solve the cube for fun, it’s best to stick with the beginner method . On the other hand, if you get stung and want to go deeper, the advanced method will keep you busy for many weeks.

Whether you opt for one method or another, the cube is solved by applying a series of mathematical algorithms. The first steps in both one method and the other are made by moving the pieces exactly like a puzzle until they form a complete face and the central layer is well placed. From there, in both methods we will have to apply a series of algorithms to solve the cube . Each step has its own algorithm, which we could define as a sequence of movements where the ‘input’ will be the same, since the output will be the same.

Beginner Method

The basic method is composed of 7 steps . Before you start, you should have figured out how to move the pieces around the cube.

1. Locate the white face (the one with the white center) and form a white cross around it. The secondary color of the edge must match the center piece of the other face of the cube.
2. Put the white edges back in place . There are three possible cases, which are solved with the following algorithms:
   • White color on the right: R’ D’ R
   • White color on the left: FD F’
   • White base color: FL D2 L’ F’
3. Complete the second layer by correctly locating the edge. Place the edge on the face on which the piece goes correctly and execute the following algorithm:
   • If the turn is to the left: U’ L’ ULF U’ F’
   • If the turn is to the right: UR U’ R’ U’ F’ UF
4. Now it’s time to make a yellow cross , just like at the beginning, but without spoiling everything we’ve done. It does not have to be aligned with the color of the other face. We’ll do that in step 5. To rotate the edges, we’ll do the FRU R’ U’ F’ algorithm.
5. We place the yellow pieces in their corresponding place with respect to the central color of the other faces. This step should be repeated until everything is well aligned: RU R’ UR U2 R’ U.
6. Bring the vertices to their place . It doesn’t matter if the orientation is correct or not. The algorithm this time is as follows: UR U’ L’ U R’ U’ L
7. Guide and solve . The last step is the easiest of all. It consists of repeating the R’ D’ RD algorithm until all the corners are correctly oriented. That done, implement you will have to move the faces horizontally to solve the cube.
   Advanced Method or Friedrich Method (CFOP)

   

   The above method is interesting to solve the cube in about 30 seconds or a minute if you have a lot of skill. However, the advanced method allows you to solve the cube in very few seconds . It is named after its creator, Jessica Friedrich . The method consists of 120 algorithms in total , so you have to have a lot of memory and spend many hours on the cube to learn the technique. However, there is an alternative version to the complete Friedrich method, which is the Reduced Friedrich. In this case, it ‘s 49 algorithms , but you’ll have to do a lot more steps.

   Rubik’s Cube Records

   If you find it difficult to solve the Rubik’s Cube, it will seem even crazier that some are able to solve it with their eyes closed, with their feet or even with one hand. These are the current records:

   • Yusheng Du (CH) – 3.47s – Two-handed record (2021)
   • Max Park (USA) – 6.82s – One-handed record (2019)
   • Sebastiano Tronto (IT) – 16 – Record with the fewest moves (2019)
   • Tommy Cherry (USA) – 14.67s – Blindfolded ( 2021)
   • Graham Siggins (USA) – 59/60 59:46 – Blindfolded Multi (2019)
   • Que Jianyu (CH) 5 min, 2.43s – Multi 3 with juggling (2020)