Centers and edges are fully reduced. The first two virtual layers are solved.
Yellow up. Put a group that is not yellow-up at top-front (UF).
1. Recognize the actual parity case
Count the yellow-up edge groups, ignoring corners. After two virtual layers are solved, one or three yellow-up groups indicates OLL parity. OLL here refers to last-layer orientation.
Every group must already contain two matching wings. Two unmatched wings belong back in pairing; they are not a flipped reduced edge. If zero, two, or four groups face yellow up, use the ordinary 3×3 cross cases instead.
2. Place the target at top-front
With three yellow-up groups, place the fourth group at UF. With only one yellow-up group, choose any of the three that are not yellow-up and put it at UF. Flipping it will produce an ordinary two-edge case.
Use a sideways whole-cube rotation or U before the sequence as needed. Keep yellow up at the start.
3. Follow the complete repair
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 centers halfway through the repair.
4. Return to the solve
After completing every move, reorient the cube with yellow up. Check that centers and edge pairs are restored. Recount the yellow-up edge groups and return to the yellow-cross lesson if the cross is not already complete.
Other last-layer pieces may still need solving. The repair removes the orientation exception; it is not a promise to finish the entire cube. You may encounter PLL parity later even after 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 is 90° clockwise looking directly at that face. An apostrophe (′) reverses it; 2 means 180°. Keep the front fixed during an 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
Use one move at a time first. This prepared case teaches a specific action; use the lesson’s setup instructions to recognize when it 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. Arrow keys rotate the view when the cube is focused.
Copy this exact example on your own cube
Start with a solved 4×4, yellow up and blue front. Apply the setup below from left to right. This creates the example’s starting position. Keep this separate from the ongoing scramble you are solving through 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’s color scheme differs, match the piece relationships using your own colors.
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 the case during a solve, pause at the yellow cross. Put the target at UF, follow every move, then restore yellow up and recognize the new cross case.
Open a 4×4 Digital Cube for practiceOpens in a new tab so you can keep this lesson beside your practice. Check the lesson goal yourself; the Digital Cube does not grade it.
If you get stuck
The animation’s front changed during the sequence.
x is a real whole-cube rotation. Follow it and use the new face directions for the remaining moves.
The cube is not fully solved after parity.
Recheck the yellow cross and continue normal last-layer solving. The repair only fixes the flipped-group exception.
Before moving on
Check your result
Your cube at this stage
The flipped-edge case repaired
The edge groups are paired and yellow-edge orientation is normal again. This example has a yellow cross; corner work still remains.
Confirm these on your cube. Watching the animation alone does not complete the lesson.
Check every item when you can do it yourself.