How the cube works

Fifty-four stickers

Here it is: a scrambled cube. Six faces, nine stickers on each, fifty-four in all. See it as a mosaic of colored squares and it looks hopeless — tidy up one face and the face 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 evaporates. Nine chapters from now you'll be able to solve it from any position. We'll begin by simply peeking inside.

A look inside

Let's pull the cube apart. From the outside it seems to be a stack of twenty-seven little cubes, but the one in the very middle isn't there. In its place is a core: a spindle with six arms pointing in six directions. The face centers sit at 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 in the middle of a face. It's fixed to the core, and it can do only one thing: spin in place. Watch the cube turn one face after another — the highlighted centers never leave their posts. That's why white is always opposite yellow, green opposite blue and red opposite orange.

Which brings us to rule number one: the center decides the color of the face. The face with the yellow center is the yellow face, even if it has no other yellow sticker on it right now. We never ask "where should the green face be?" — it's wherever the green center is. The question is always the same: which pieces haven't made it to their centers yet?

Edges: twelve with 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. And there's no such thing as a white-yellow edge: opposite colors never meet on the same piece.

Corners: eight with three colors

A corner is a piece with 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 will ever put a corner where an edge should be. So when you look for a piece's home, you only need to search among its own kind: a corner among the eight corner spots, an edge among the twelve edge spots.

Solve pieces, not colors

The bottom face of this cube is all white. Job done? Not quite. Look at the bottom row on the front and on the right: those stickers don't match the centers above them. The white face is solved by color, but the 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, turned the right way round — get that, and the colors take care of themselves. Here a single turn of the bottom is enough: 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 you'd need over a trillion years to see them all, roughly a hundred times the age of the universe. So twisting at random and hoping it will sort itself out is a lost cause. You need a method.

Now for a stranger fact. Take the cube apart, put the pieces back in at random, and it 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 only flip 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 the last chapter it will pull off a small miracle.

The cube from Budapest

In 1974 Ernő Rubik, a young architecture lecturer in Budapest, was looking for 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 came up with was a mechanism he called the Magic Cube.

Then came the funny part. Rubik scrambled his invention and couldn't put it back: his first solve took him about a month. Unlike you, he had no instructions. In 1980 the cube went on sale around the world 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; we'll get to those in the next chapter.

Why yellow up and not white? We'll finish the white layer on the bottom, but we'll 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 get turned around, check the centers. They aren't going anywhere.

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

Next: the language of turns

So the cube is six fixed centers, twelve edges and eight corners. Each piece has to reach its own centers and sit the right way round. 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 misery. 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 you'll play your first one, the famous sexy move, before that chapter is over.