Troubleshooting¶
"My cube is impossible to solve"¶
Nine times out of ten that is true — and it is not your fault.
A cube taken apart and reassembled at random has an 11 in 12 chance of being in an impossible state. No method will solve it, because no sequence of moves can get there.
Here are the three signatures of a tampered cube. All of them show up right at the end, when everything else is solved.
A single flipped edge¶
Everything is solved except one edge, in its place but flipped.
That is impossible on an intact cube. Edges necessarily flip in pairs.
A single twisted corner¶
Everything is solved except one corner, in its place but rotated a third of a turn.
Equally impossible. The sum of the corner twists is always a multiple of three.
Two pieces swapped¶
Everything is solved except two edges — or two corners — that need swapping.
Also impossible: a single swap changes the parity, which no 3×3 move can alter.
The fix¶
Take it apart and reassemble it properly.
- Turn the top face 45°, and lever out an edge with a flat screwdriver or your fingernail. It comes out without breaking.
- Take the rest apart, piece by piece.
- Reassemble it directly in the solved state, colour by colour. Corners last.
Never reassemble a cube at random
That is exactly how the problem is created. Always reassemble it solved.
Another possible cause: the stickers
On old sticker cubes, somebody may have peeled one off. Check that you have 9 stickers of each colour, and that the opposite-colour pairs are consistent (white↔yellow, green↔blue, red↔orange).
"I break everything on the last step"¶
This is by far the most frequent problem, and it has a single cause: you turned the whole cube during step 7.
While orienting the corners you must only do U moves between the repetitions of
R' D' R D. The cube must stay rigorously still in your hands.
If it is already broken: start the cube again from step 1. It will be quick, you know the way.
"The cube looks destroyed in the middle of an algorithm"¶
That is normal and intended. Most algorithms pull out pieces that were already solved, manipulate them, then put them back.
The rule: never stop in the middle of an algorithm. Always go to the last move. If you are unsure where you are, it is better to restart the algorithm from the beginning than to carry on guessing.
"I can't find the piece you are talking about"¶
Two landmarks unblock nearly everything:
- The centres never move relative to each other. The green centre is the green face, definitively. Always search relative to the centres.
- A piece never changes family. A corner has three colours and stays a corner; an edge has two and stays an edge. If you are looking for a green-orange piece, it is an edge: do not look for it among the corners.
"I have two identical colours next to each other"¶
Impossible on an intact cube: every piece is unique. If you see two green-orange edges, your cube has stickers in the wrong place, or it is a counterfeit with an incorrect sticker set.