# How to solve a Rubik’s Cube Written by Vidar Klungre

A couple of weeks ago, I was one of the organizers of the Norwegian Rubik’s cube championship. *“What!? Does that even exist?”*, you ask. Yes, it does. There are people in this country who practice hours every day, and call it a sport. A sport which is so nerdy that it deserves a blog post here.

*The original 3x3x3 together with other puzzles used in the competition.*

## Rubik’s what?

So I assume that everyone knows what a Rubik’s cube is. This twisty puzzle that we all own, but can’t solve. When I was about 15 I got my first Rubik’s cube, and I solved it! I did not come up with the solution myself of course - that takes years. What I did was that I searched for a guide online. I found a good one, and by the end of the day I could solve it in about 5 minutes. The coming days my times improved drastically. The challenge was no longer to actually to solve the cube, but to solve it fast! I had become a “speedcuber”.

## A sport for everyone

So this April over 100 kids, youths, students and parents met at the University of Oslo to fight for the title “Norwegian Rubik’s Cube Champion”. The competition was open to everyone who could solve the cube. People was coming from all over Norway, and even other countries like Sweden and Hungary was represented!

*Competitors solved the cube on the stage, and live results appeared as they were registered.*

Some of them considered themselves being speedcubers, while others showed up to support their friends, or maybe to try to learn how to solve the puzzle. Each competitor could participate in up to a total of 17 different categories, some of which included solving the cube with only one hand, blindfolded and even with their feet! In some categories other puzzles than the normal 3x3x3 was used. For each category there were multiple rounds, and for each round each person solved their puzzle five times, in order to get an average. So all together during the weekend, people solved cubes over 5000 times!

## And the winner is…

The winner of the main category, 3x3x3, was Morten Arborg (17). He solved the cube with an average of impressing 9.32 seconds in the final round. His best solve during the competition was 7.28, which is the fastest time done by a Norwegian ever, and which ranks him number 25 in the world.

*Morten Arborg received a trophy and a check for winning 3x3x3.*

To compare, the world record, set by the 16 years old Dutch speedcuber Mats Valk, is 5.55 seconds. Here is the video of him showing us how to do it:

## Optimal solution?

In 2010 researchers proved that any configuration of a Rubik’s cube can be solved optimally in 20 moves or less. The team, most of them from Silicon Valley, used about 35 CPU-years of idle computer time donated by Google to essentially solve every possible configuration. If you learn a standard beginners method online, you will probably be able to solve the cube by doing about 150 moves, while the best speedcubers in the world solve it by only doing about 50 turns.

Mats Valk did his 5.55 solve in 49 moves. That was by no mean the optimal solution, but it is still pretty good, especially when we know how fast he did it. Also, he is just a human, so what can we expect? Mats does not calculate the optimal solution, but he divides the problem into substeps, and solve all of them optimally. He knows over 200 different algorithms, which he uses to modify the cube towards the solved position. Also, he is incredibly fast at both recognizing patterns, and to perform the corresponding algorithm. The best speedcubers do over 10 turns per second. To understand how fast this is you should check out the video of Mats, or try it out yourself.

## I bet a computer can do it faster!

So who is the fastest at solving the Rubik’s cube? Humans or computers? If we only care about finding a solution, computers are the winners. They can calculate the optimal solution for any configuration of the cube in a matter of seconds, while no human being are able to do that as far as I know. But when we add the requirement to actually make turns on a real Rubik’s cube, the robots gets a problem. Humans are much better at manipulating the cube, and before 2011 I had never seen any robots faster than the current world record holder.

Then I stumbled upon this video of StormCuber II. This robot made out of Lego Mindstorms, connected to a smartphone solves the cube in less than 5.3 seconds. This is also included inspection time, as opposed to the human world record, which makes it even more impressive.

## So go buy yourself a cube!

After reading this blog post, I hope you got inspired to buy yourself a new cube, or to blow the dust of the old cube you already have. Try to solve it by yourself, find a guide online, or get a set of Lego Mindstorms. If this four year old kid can do it, then you should be able to do it as well:

comments powered by Disqus