How the cube works

Fifty-four stickers

Here's a scrambled cube. Six faces, nine stickers on each, fifty-four in all. Treat it as a mosaic of colored squares and the job looks hopeless: tidy up one face, and the one next door falls apart.

The good news is that the mosaic is an illusion. The cube is far simpler than it looks, and once you see what it's made of, half the fear melts away. By the end of chapter 9 you'll be able to solve it from any position. But first, let's simply peek inside.

A look inside

Let's pull the cube apart. From the outside it looks like a stack of twenty-seven little cubes, but the one in the very middle is missing. In its place sits a core: a hub with six arms sticking out in six directions. The face centers ride on the tips of those arms, and every other piece hooks its little feet around the centers and around its neighbors. The result is a puzzle that turns and turns but never falls apart.

Twenty-six pieces show on the outside, and they come in exactly three kinds.

Centers: six beacons

A center is the piece with a single sticker, right in the middle of a face. It's anchored to the core and can do only one thing: spin in place. Watch the cube turn one face after another. The highlighted centers never leave their posts, which is why white is always opposite yellow, green opposite blue and red opposite orange.

That gives us rule number one: the center decides the color of the face. The face with the yellow center is the yellow face, even if not one other sticker on it is yellow right now. We never ask where the green face should be. It's wherever the green center is. The only question worth asking is this: which pieces haven't reached their centers yet?

Edges: twelve pieces, two colors

An edge sits between two centers and carries two stickers. There are twelve of them: four around the top face, four around the bottom and four in the middle layer.

Every edge has exactly one rightful place. The white-green edge lives between the white and green centers, and nowhere else. There's no such thing as a white-yellow edge, either: opposite colors never meet on the same piece.

Corners: eight pieces, three colors

A corner has three stickers, and there are eight of them. The white-green-orange corner lives where the white, green and orange faces meet.

Notice that a corner always stays a corner, and an edge always stays an edge: no turn can ever put a corner where an edge belongs. So when you hunt for a piece's home, you only have to search among its own kind, a corner among the eight corner spots and an edge among the twelve edge spots.

Solve pieces, not colors

Peek underneath this cube: the bottom face is solid white. It looks finished. Your first color is done!

Don't celebrate just yet. Let's look at the same cube from the side.

A fake white face

Check the bottom row on the front and on the right: those stickers don't match the centers above them. The face is all white, but its pieces are sitting in the wrong places.

This is the most common beginner's trap. The goal isn't a face of one color. It's every piece in its own place, facing the right way. Get that, and the colors take care of themselves. Here a single turn of the bottom does it: D', and everything snaps into line.

A number to make your head spin

The cube has 43,252,003,274,489,856,000 positions, more than forty-three quintillion. Visit a new one every second, and seeing them all would take over a trillion years, roughly a hundred times the age of the universe. Twisting at random and hoping it sorts itself out is a lost cause. You need a method.

Now for something stranger. Take the cube apart, snap the pieces back in at random, and the result will be solvable only one time in twelve. Blame three hidden laws:

• you can't twist a single corner on its own: the twists of all the corners always add up to whole turns;
• you can't flip a single edge: edges flip only in pairs;
• you can't swap two pieces and leave everything else alone.

Three times two times two makes twelve. Hold on to that first law. In chapter 9, the last step of the solve, it will pull off a small miracle.

The cube from Budapest

In 1974 Ernő Rubik, a young lecturer at the Academy of Applied Arts in Budapest, wanted a hands-on way to show his students how the parts of a structure can move independently without the whole thing falling apart. What he built was a mechanism he called the Magic Cube.

Then came the funny part. Rubik scrambled his invention and couldn't undo the mess: his first solve took him about a month. Unlike you, he had no instructions. In 1980 the cube went on sale worldwide under its inventor's name and became one of the best-selling puzzles in history.

How to hold the cube

Throughout this course we hold the cube the same way: yellow center on top, white on the bottom, green facing you. That puts orange on the right, red on the left and blue at the back. The letters on the faces are their names, and the next chapter is all about them.

Why yellow up and not white? The white layer ends up on the bottom, but we start building it on top, around the yellow center. That way you never have to flip the cube over mid-solve and try to remember what was where. And if you ever lose your bearings, check the centers. They aren't going anywhere.

Try it yourself. Someone has turned one face. Figure out which one, and turn it back.

Next: the language of turns

Let's take stock: the cube is six fixed centers, twelve edges and eight corners. Each piece has to reach its own centers and face the right way. Not so scary after all, is it?

Now you need a way to talk to the cube. Describing turns in words ("the right side away from you, no, the other right") is torture. In the next chapter you'll learn a compact language: six letters, a prime and a 2. Every technique in this course is written in it, and before that chapter is over you'll play your first one, the famous sexy move.