Solving Rubik's Cube

Sat, 08 Sep 2007 18:37:12 GMT

A kid, about 5, popped over to my house and started playing with my Rubik's cube last night. I've tried to solve the cube on my own a fair few times before, but I haven't been successfully.

Since I am mostly relaxing at home this APEC holiday weekend, I've decided to look for a way to solve the cube. It's surprisingly easy if you have the techniques right in front of you to follow. There are only really about 5 move sequences that you need to remember, the rest is pretty straight forward (a bit of logic, nothing too fancy). Trust me, before I used these techniques I thought I needed to have photographic memory to do this thing, but now I think anyone can do it.

The instructions I've used can be found here. Don't use it if you decide to try, it's too verbose. I've ignored most the instructions and simply used the 5 moves and 4 goals found in there to solve my cube. I don't think it's the most efficient way to solve the cube, but it works. Here's a shortened version of the technique (all pictures I've used have been taken from the original source).

Rubik's Cube Instruction - a 4 step process

Let's disambiguate with some illustrations, the Rubik's cube has 6 faces and 26 cubes that needs to be rearranged in order to solve it. Like any other puzzle there's only one location where each cube can go.

1. The first step is to get a cross on one face of the Rubik's cube, choose any colour you wish.

2. The second step is to get a cross on all 6 faces of the Rubik's cube.

3. The third step is to get all the corner cubes in the correct corners, e.g. the corner cube for red, blue and yellow faces must have all 3 colours. Note: we are not solving the cube yet, so the orientation of the corner cubes are not important. Just get the corner cubes in the corner where they belong (Remember there's only one location where each cube can go).
4. The final goal is to solve the Rubik's cube by reorienting(turning) the corner cubes to match each face of the cube.

The first goal is relatively straight forward, so just do it yourself! The 2nd goal and 3rd goal will need some techniques to follow. The techniques I refer to here are move sequences that will allow you to move a cube to a desired location yet retaining the position of most of the existing cubes.

You will need the following 5 move sequences
1. EDGE SWITCHER
2. EDGE SWITCHER WITH FLIP (use sequence 1 & 2 until you complete step 2)
3. SWITCH THREE CORNERS (use sequence 3 until you complete step 3)
4. CORNER FLIPPER RIGHT
5. CORNER FLIPPER LEFT (use sequence 4 & 5 to complete the final step)

See illustrations below for each of these move sequences.

The EDGE SWITCHER sequence.
Hold the cube like this before performing this sequence.

The EDGE SWITCHER WITH FLIP sequence
Hold the cube like this before performing the moves.

The SWITCH THREE CORNERS sequence.
Hold the cube like this before performing this sequence.

The CORNER FLIPPER RIGHT move sequence.
Hold the whole cube like this before performing the sequence.

The CORNER FLIPPER LEFT sequence.
Hold the whole cube like this before performing the sequence.

My finished cube :)

if i remember correctly it took me about 2 hours the first time i did it, but now i can do it in 20 min by following the sequences. If i remember the sequences i could probably cut that down to about 5 min. I've just been taught a new way to do it by another kid (about 16 years old) and it's much faster, I will post the new instructions later.

James Zhuo 卓宇翔: Hobbies

Solving Rubik's Cube