Have you ever looked at a scrambled Rubik's Cube and felt like you were looking at a six-sided padlock with no earthly combination? Well, believe it or not, Rubik's Cube does have a combination. And it's only ten numbers long. Here it is:
You won't set any speed records using it, but those ten numbers are all you need to solve the Cube. Write them down or copy them into the notes on your smartphone. You never know when you'll run into an unsolved cube.
First, a little background:
Speedcubing is for Cubers (Yes, it's a thing. And so are they) who use all manner of notation to describe the ways they manipulate every piece and plane of 'the Cube' - with algorithms that allow them to solve it in well under 20 seconds. Each face of the cube is assigned a letter (U,R,D,B,etc). Each center slice gets its own letter. To describe turning them counter-clockwise requires a subscript "i" or superscript -1, etc, etc. The nomenclature can get deep quickly.
Well, relax. This ain't one of those methods.
This variation on (what has come to be called) the Beginner's Method assumes you've got a good five minutes to kill, and no one to impress but yourself.
I was in that particular boat a few weeks ago. I hadn't touched a cube since the late 1980s, but had vague memories of having been able to solve it (albeit, slowly). I decided to see if I could again memorize a solution.
You can find several simple 7-step Beginner's Method solutions to the Cube online (most are slight variations of the general layer-by-layer approach credited to mathematician David Singmaster, first published in his 1981 book Notes on Rubik's Magic Cube), but one of these Beginner's Method variations in particular lends itself to a 'By The Numbers' approach, so I'll be picking on that one. Dénes Ferenc has a couple of the best illustrated versions of it on the internet.
The official Rubik's Cube I bought came with an easy-to-understand solution developed by Dan Knights (now Dr. Dan Knights), the 2003 3x3 Speedsolve World Champion. It wasn't advertised as an easy-to-memorize solution, or even a fast solution; just an easy-to-understand one. It did the trick for me. Almost.
This layer-by-layer approach was not the method I'd memorized in the '80s when 'the Cube' was still TIME's Hungarian Horror. This was better; a bit easier. And it seemed to me it had two elegant attributes that more advanced and speedier methods just don't have. First, except for maybe the initial simple step, none of the steps involve turning any of the center rows. You only 'dial' whole faces of the cube. Second, only five of the six faces ever get turned. You can forget about the back face.
The moves were simple enough. It was the notation that seemed over-engineered for the job.
So I started looking for a more intuitive way to describe the layer-by-layer method.
I guess I'm more of a numbers guy.
Rather than assigning letters to the faces of the Cube, assign them numbers.
Holding the cube in front of you, imagine the top face is 2, the right face is 4, the face straight in front of you is 6, left face 8, and bottom face 10. Forget the back face that's furthest from you. It doesn't need a number.
In this Safecracker Method's nomenclature, 'even numbers' mean you should dial that face one quarter turn clockwise. If you are meant to turn a face counter-clockwise, we'll just subtract 1. So, on paper, turning face #6 clockwise would be expressed simply as "6" and turning face #6 counter-clockwise would be expressed as "5".
That's all there is to it.
Note: You might find it easier to practice all this on a 'virtual cube' -- inside the official Rubik's Cube smartphone app -- than on a 'real cube'. The app (free, as of this writing) has one very helpful feature -- a "Back" button to retrace your steps to the point where you think you messed up. A real cube is far less forgiving.
Just to be clear on Notation:
10 = Turn face #10 one quarter turn clockwise.
Let's get crackin'
Solve a Single Face. I don't have any instructions for this. It's not hard. Just do it. After you solve one face (blue in the following example), spin the 'equator' beneath it until the colors of the side-centers align correctly (in this case, the white and red center pieces). Your cube should look like the one below. This is your starting point. From here, ten numbers are all you need to unlock the solution.
Step 1 : Dial 2413-1526 to Solve the Middle Layer Edges.
In truth, you can solve the entire middle layer using only 2413-1526, it just takes longer to power though with only the one combination. Making smart use of its inverse (1526-2413) will knock at least 30 seconds off your time.
Step 2 : Dial 642-315 to Solve the Upper Cross.
Step 3 - Dial 4232-4223 to Fix Those Top Edges.
Step 4 - Dial 2417-2318 to Solve the Top Corners (positions).
Step 5 - Dial 394-10 to Solve the Top Corners (colors).
Step 6 (optional, quoting from David Singmaster in his 1981 book)
Now you're done.
Acknowledgments & Notes
So is this a new method for solving Rubik's Cube?? Hardly. At best it's a new twist on a forty-year-old problem. In computer terms, it's hacking a new 'user interface' onto a tried-and-true program. The layer-by-layer approach goes back at least to Singmaster's solution in the early 1980s -- refined, illustrated and popularized anew in the internet age by the likes of Knights in print and Ferenc, Jasmine Lee and others online. Its popularity stems from its use of very few move sequences (err, algorithms) that repeat often - leading to it commonly being referred to as The Beginner's Method. The 'Safecracker Method' is new only in nomenclature. But if dialing the 10 numbers of Safecracker helps you get through the memorization phase and enjoy the cube, maybe it has some merit. Let me know what you think. Can you design any other 'By The Numbers' / numerical solutions to Rubik's Cube? I'd love to hear about it.
About Ernő Rubik
While there's no 'right way' to solve a cube, there are some that seem a bit less right:
If you're young and/or still have a heap of un-allocated brain cells, you might take to Speedcubing. It's a whole other world -- full of notation, nomenclature, finger tricks, and algorithms galore. For that, you will inevitably end up on these two websites:
If you find yourself outgrowing the Safecracker Method, here's a primer for translating into the notation of speedcubing:
Copyright Todd Schannuth 2016 - 2017