Way of Cube Back to the cube

Twisted corner? Fix a Rubik's cube that is impossible to solve

If the cube will not come together no matter what you try, it is probably not you. At some point a piece was twisted in its spot or moved into a place turning could never have put it, and from then on no sequence of turns will ever solve that cube.

This is one of the most ordinary things that happens to a cube, and it happens to everybody. Five minutes with your fingers puts it right, and the cube is as good as it ever was.

One check first. If you are partway through the last stage and the cube suddenly looks wrecked, that is the method working, not a broken cube: see why the last corner will not solve. If a piece has come right out, start with putting a popped piece back.

A twisted corner

How to recognise it

You get all the way to the end and one corner piece is in exactly the right place, with exactly the right three colours, but rotated. Its colours are a third of a turn out from the pieces beside it: the yellow that should be on top is facing sideways, and the side colour that should be facing you is pointing up. Everything else on the cube is finished.

The giveaway is that it is only one. Two corners twisted in opposite directions, or three twisted the same way, is an ordinary part of the last stage, and the method sorts them out. A single corner twisted on its own, with every other piece home, is never something the method left behind.

Why turning can never fix it

Turning a face twists corners in sets that cancel each other out, so one corner left over twisted on its own is not something any number of turns could have made, and not something any number of turns can undo.

How to mend it

  1. Turn the sides of the cube until the twisted corner is on the top layer, where you can get hold of it.
  2. Turn the top layer about half way between two positions, so the corner stands proud of the rest of the cube and is easy to pinch.
  3. Hold the cube still in one hand. With the other, take that corner piece between finger and thumb and turn it in its own spot, a third of a turn at a time, without lifting it out.
  4. Stop when its colours line up with its neighbours: the top colour on top and each side colour facing the same way as the pieces next to it. Straighten the top layer again and carry on solving.

Which way to twist it

Find the sticker that belongs on top and twist the corner so that sticker moves up onto the top face. If you pick the wrong way, nothing is harmed: keep turning the same way, and two more thirds of a turn bring it home just the same.

A stiff or a brand new cube can need a firm pinch here. It is meant to click rather than crunch, so if it will not go, turn the top layer a little further off square first.

A flipped edge

How to recognise it

One edge piece, the kind with two colours, is sitting in the right slot the wrong way round: its two colours are each on the face the other one belongs on. It shows up at the very end of the solve, usually as a single edge that refuses to flip however many times you run the sequence, while every other piece is already home.

Why turning can never fix it

Every turn flips edges two at a time, so the number of backwards edges on a real cube is always even. One on its own can only have got there by hand, and only a hand can take it back out.

How to mend it

  1. Turn the sides until the backwards edge is in the middle of the top layer's front edge, then turn the top layer about half way between two positions so that edge sticks out past the corner below it.
  2. Lever the piece out from underneath with a thumb, or with something flat and blunt like the handle end of a teaspoon. It comes out with a pop and nothing breaks.
  3. Turn the piece over so its two colours swap sides, and push it back into the same slot until it clicks.
  4. Straighten the top layer, and the cube is solvable again from wherever it stands.

This one is worth a grown-up's hands. Levering a piece out takes more force than a child expects, and a cube that flies apart on the carpet is how the next fault on this page usually starts.

Pieces put back wrong

How to recognise it

The cube came apart at some point, on purpose or on the floor, and was pushed back together in whatever order the pieces came to hand. Two of them ended up in each other's homes. At the end of a solve you are left with two pieces that each need to be where the other one is, and swapping just those two is the one thing the method never asks for.

Why turning can never fix it

A turn always moves pieces around in rings of four, and no number of those rings ever adds up to a single pair traded. Two pieces put into each other's homes stay a pair the cube cannot untangle.

How to mend it

  1. Bring both pieces to the top layer, one at a time, and pop each one out the same way as a flipped edge: turn the top layer off square so the piece stands proud, then lever it out from underneath.
  2. Put each piece into the slot the other one came from.
  3. Check the colours as they go in. A piece can be right in its slot and still the wrong way round, so line each one up with the centre colours around it before pressing it home.
  4. Straighten the layers and solve as usual. If the cube still will not finish, come back to sections 1 and 2: a cube that was rebuilt often has a twisted corner as well.

Corners and edges are different shapes and will not go into each other's slots, which means a rebuilt cube only ever has corners traded with corners and edges traded with edges. That narrows the search a great deal.

Let the app find it for you

Working out which of the three faults you have by staring at a mixed-up cube is the hard part, and it is the part a computer is good at. Way of Cube can look at your actual cube and tell you.

Hold your real cube up to the camera and show it each of the six sides. The app reads the colours, then checks whether that scramble is one a real cube could ever be turned into. If it is not, it says so, lights up the exact piece that is wrong on a 3D cube you can spin with a finger, and shows you which way to mend it. There is a button for when you have done it, which takes you back through the camera to check your repair worked, and then it teaches you the whole solve from the cube in your hands.

Scan my cube

Free, no account, and the camera pictures never leave your device.

New here? About Way of Cube explains how the lessons work and what age they suit.

More help

Questions

Why does my cube feel unsolvable?

Almost always because one piece is in a state that turning cannot produce: a corner rotated in its own spot, an edge sitting backwards, or two pieces in each other's homes. A cube like that looks exactly like an ordinary mixed-up cube, which is what makes it so maddening. You follow every step of the method correctly and the last few pieces simply refuse to land.

Did I break my cube?

No. Twists and pops happen constantly, to everybody, and nothing about them is permanent: the plastic is fine and the cube is not worn out. A piece has been put somewhere it could not have turned its way into, and putting it back is a repair of seconds rather than a reason for a new cube.

Do I need to take the whole cube apart?

Almost never. A twisted corner turns in place with your fingers and never leaves the cube at all. Only a flipped edge and a swapped pair have to come out, and that is one or two pieces levered out of the top layer, not fifty-four stickers and a pile of parts on the table.

How do I know if my cube has a twisted corner?

Solve as far as you can. If every piece is home except one corner, and that corner is in the right place with the right three colours but turned a third of a turn, it was twisted by hand. Two or three corners turned at once is normal and the last stage of the method fixes them; one on its own never is.

You can also find out without solving at all: scan the cube with Way of Cube and it says whether a corner is twisted, and which one.

How do I fix a twisted corner without taking the cube apart?

Turn the top layer about half way off square so the corner stands out, hold the rest of the cube still, and twist the corner in its own spot with finger and thumb until its colours match the pieces beside it. It never leaves the cube. The full steps are in section 1 above.

Can a corner twist by itself?

Yes, mostly on a loose cube. Turning a face hard while another layer is not lined up can catch a corner and turn it in place, and so can a drop. Sometimes a brother or sister does it as a joke. Keeping each layer square before turning the next makes it much less likely.

Why won't the last corner solve?

Most of the time the cube is fine. During the last stage the cube looks messy on purpose, and it only comes back if you turn just the top layer between corners and never turn the whole cube. If everything else is solved and one corner is still turned, that is a twisted corner. More on the last corner.

Is it parity? Can a 3x3 cube have parity?

Not the way a 4x4 can. On a 4x4 or bigger cube, parity is a position that looks impossible but has a special sequence of turns to fix it. A 3x3 has no such case. If a 3x3 seems to need one, such as a single flipped edge or just two pieces swapped, a piece was moved by hand, and the fix is by hand too.

A piece popped out. How do I put it back?

Turn the layer it came from about half way off square, line the piece's colours up with the centres around the gap, and press it in until it clicks. Which way round it goes matters, or the cube ends up with a twisted corner or a flipped edge. Putting a popped piece back.

What does it mean if my cube is warped?

People mean one of two things. If a layer has just been knocked out of line so the cube looks bent, turn each layer back until it is square and it is fine. If the plastic itself has bent, usually from heat such as a hot car or a dishwasher, the cube will keep catching and popping, and it is time for a new one. Loose, stiff and warped cubes.