3x3 · COLL
3x3 COLL Pi 4 algorithm
3x3 COLL Pi 4 algorithm: 15 turns, opening with R U R'. Case recognition, the complete sequence, and practical execution notes.
Solve the last-layer corners with the last-layer edges already oriented; edge permutation may remain.
Pi 4 belongs to the Pi group in COLL.
Recognize this starting position
In the inverse-derived training position, the upper-face color points upward at these corner positions: none. Upper edges with that color facing up: UF, UL, UB, UR. Reading each side’s upper corner stickers left to right when facing that side gives F: R U; R: F L; B: U F; L: U U. The letters identify colors by their reference faces.
Execute the algorithm
R U R' U' R' F R2 U R' U' R U R' U' F'
The opening is R U R'; the final segment is R' U' F'. This version contains 15 face, wide, or slice turns and no whole-puzzle rotations.