Solving Rubik's Cube
- Introduction
- About The Puzzle
- Hints
- Notation
- 3x3x3 Solution
- Professor's Cube
- 5x5x5 Solution
- Revenge
- 4x4x4 Solution
- Beyond the 5x5x5
Notation
When solving the cube, it's essential that you have some way of writing down what moves you made and how the cube was affected by them. If you can't do that then you won't be able to remember what you've done. Here is the notation that I use. I'll be using this notation on the rest of these pages.
A cube has six faces (duh). When describing move sequences I use the abbreviations U, D, F, B, L and R for the up, down, front, back, left and right faces respectively. Which face you call "up" and which face you call "left" depends on how you have oriented the cube at the start of the sequence.
Since it's a little difficult to draw all six sides of a cube on a two dimensional plane (a piece of paper) I use a distorted view that shows five of the six sides. The sixth side doesn't need to be shown because it's assumed that it has already been solved. (You've already solved one layer on your own right?) Figure 1 shows a cube and figure 2 shows how I would diagram that cube.
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| figure 1 | figure 2 |
Note that I don't bother to show any of the sub-cubes belonging to the D (down) face at all because they are already in the correct position (with respect to each other) and it is assumed that any sequence of moves that I would be interested in would keep them that way.
Before I continue, I should note that all of the example sequences that I'm about to list on this page are useless. That's so I don't spoil the solution for those of you who want to solve it on your own. The sequences on the next page are the real thing.
Any sequence of moves can be described as a sequence of face rotations. In the notation I use, a capital letter by itself means to turn that face one quarter turn clockwise. Therefore, U means turn the up face clockwise one quarter turn. Adding a ' (prime) symbol after the letter means turn the face counterclockwise and adding 2 means turn the face 180°. So as an example: the sequence R U' L2 means turn the right face a quarter turn clockwise, turn the up face a quarter turn counterclockwise and turn the left face 180°.
I also find it's useful to represent repeated sequences by putting the sequence in parameters and adding a multiplier. For example: (R L)x2 means turn the right face a quarter turn clockwise, turn the left face a quarter turn clockwise, turn the right face a quarter turn clockwise and turn the left face a quarter turn clockwise.
Sometimes it's useful to turn a middle face. A lower-case letter means to turn the next face in. For example, u means to turn the middle horizontal row (the row directly beneath the up face) clockwise (see figure 3 below). Note that this would have the same effect as U' D followed by rotating the entire cube clockwise about the up face. For a standard 3x3x3 cube, this notation is merely a convenience but when I get to describing the moves for the 4x4x4 and 5x5x5 cubes this notation will become essential.
figure 3 - turning middle face u
Occasionally I'll break particularly lengthy moves up into pieces separated by a plus + symbol. Usually that symbol comes at a logical break where the remaining sequence of moves accomplishes an easily recognizable goal. Often the remaining sequence is a useful set of moves in its own right.
Now, if you want the satisfaction of solving the cube yourself, read no further because on the next page I'm going to describe the move sequences I use to solve a 3x3x3 Rubik's Cube.
©2004 - Steve Blanding