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Solving Rubik's Cube for speed.

By Lars Petrus

Introduction

This is a tutorial for my method of solving Rubik's Cube. It is intended both for beginners and experienced cubers. There is no group theory or written notation involved, I just show you how to move. You need a modern canvas tag capable browser, ideally with WebGL enabled.

Using this method, I won the 1981 Swedish championships, and finished 4th in the first world championships in Budapest 1982. I also won a minor world championship in 2005. As my official results show, I am a has-been these days.

Please take a look at my terminology, so you know the difference between a turn and a twist, for example.

If you are a total beginner, look at this description of the basic Rubik's Cube concepts.

The Basic Idea

Most people solve the cube layer by layer. This is a simple way for the human mind to approach the problem, but it is useless for speed cubing. No matter how good you are, you will use more than 100 moves. Going for speed, I use 55-60 moves on average. Going for few moves, I average 40-45.

The basic problem with the layer method is big, and obvious once you realize it. When you have completed the first layer, you can do nothing without breaking it up. So you break it, do something useful, then restore it. Break it, do something, restore it. Again and again. In a good solution you do something useful all the time. The first layer is in the way of the solution, not a part of it!

The Method

The Petrus method has 7 steps:

• Step 1 - Build a 2x2x2 corner
• Step 2 - Expand to 2x2x3
• Step 3 - Twist the edges — 2, 4 or 6 bad edges
• Step 4 - Finish 2 layers — Step 4b tricks
• Step 5 - Position the corners — Full Step 5+6 index
• Step 6 - Twist the corners — Full Step 6+7 index
• Step 7 - Position the edges
• Step 1, 2 & 4 - Block building tricks
• Practice - 13 example solutions

I also have some tips on the physical and mental aspects of speed cubing.

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