Centres and edges are fully reduced. The first two virtual layers are solved.
Hold the cube with yellow facing up. Put an edge group whose yellow stickers aren’t facing up at the top front (UF).
1. Recognise when you have OLL parity
Count the edge groups with yellow facing up, ignoring the corners. Once the first two virtual layers are solved, having one or three such groups indicates OLL parity. Here, OLL refers to last-layer orientation.
Every group must already contain two matching wings. If the wings don’t match, return to edge pairing. Unmatched wings don’t count as a flipped reduced edge. If zero, two or four edge groups have yellow facing up, use the usual 3×3 cross cases instead.
2. Put the target edge group at the top front
If three edge groups have yellow facing up, put the fourth at UF. If only one has yellow facing up, choose any of the other three and put it at UF. Flipping that group gives you a standard two-edge case.
Before the sequence, rotate the whole cube sideways or use U as needed. Start the sequence with yellow facing up.
3. Perform the full repair sequence
Rw U2 x Rw U2 Rw U2 Rw' U2 Lw U2 Rw' U2 Rw U2 Rw' U2 Rw'
Read this in chunks, keeping the letters in the same order:
Rw U2 xRw U2 Rw U2 Rw' U2Lw U2 Rw' U2Rw U2 Rw' U2 Rw'
Rw and Lw each mean two layers. x rotates the whole cube like R; use the new face directions after that rotation. Do not judge the centres halfway through the repair.
4. Return to the solve
Once you’ve completed the full sequence, turn the cube so yellow faces up. Check that the centres and edge pairs are restored. Count the edge groups with yellow facing up again and return to the yellow-cross lesson if the cross is still incomplete.
Other last-layer pieces may still need solving. This repair only fixes the orientation parity case. You may still encounter PLL parity later, even if this repair succeeds.
Need a reminder of the move notation?
R right · L left · U top · D bottom · F front · B back. A plain letter means a 90° clockwise turn as you look directly at that face. An apostrophe (′) reverses the turn. A 2 means a 180° turn. Keep the same face towards you throughout the algorithm.
Rw turns the rightmost two layers together. 2R turns only the second layer from the right. 3Rw turns three layers. x rotates the whole cube like R, so the old front becomes the new top.
Watch, then try
Work through an example
Start by stepping through the example one move at a time. This example demonstrates a specific action. Use the lesson’s setup instructions to recognise when that action applies to your own scramble.
Watch one worked example
The prepared cube has its flipped pair at UF. Notice the whole-cube x rotation, two-layer wide turns, and the restored edge pair at the end.
Example grip: yellow up · blue front · red right at the start. Follow any written whole-cube rotations.
0 / 18
Loading 3D cube…
Prepared position · 0 / 18 moves
Use Next move to follow the sequence.
Drag to inspect other faces. When the cube has focus, use the arrow keys to rotate the view.
Copy this exact example on your own cube
Start with a solved 4×4, with yellow on top and blue at the front. Apply the setup moves below from left to right. This gives you the starting position for the example. Keep this separate from the scramble you’re solving throughout the course.
Rw U2 Rw U2 Rw' U2 Rw U2 Lw' U2 Rw U2 Rw' U2 Rw' x' U2 Rw'Then follow the lesson sequence. If your cube has a different colour scheme, use your own colours to identify the corresponding pieces.
Compare the starting position and the result
Drag each cube to inspect its other faces.
Explain it to yourself
Check your understanding
Now use your own cube
Your turn
If you encounter this case during a solve, pause at the yellow-cross step. Put the target at UF and complete every move. Then hold the cube with yellow facing up again and recognise which cross case you have.
Open a 4×4 Digital Cube for practiceThe Digital Cube opens in a new tab so you can keep this lesson open while you practise. Check for yourself whether you’ve met the lesson goal, as the Digital Cube doesn’t assess your result.
If you get stuck
The front face changed during the animation.
For x, rotate the whole cube, then use the new face directions for the remaining moves.
The cube is not fully solved after parity.
Check the yellow cross again and continue solving the last layer as usual. The repair only fixes the flipped edge group.
Before moving on
Check your result
Your cube at this stage
Flipped edge group fixed
The edge groups are paired, and the yellow edges can now be oriented as usual. This example has a yellow cross, but the corners still need solving.
Confirm these on your cube. Watching the animation alone does not complete the lesson.
Tick each item when you can do it yourself.