3x3 · COLL
3x3 COLL U 4 algorithm
3x3 COLL U 4 algorithm: 13 turns, opening with F R U'. 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.
U 4 belongs to the U group in COLL.
Recognize this starting position
In the inverse-derived training position, the upper-face color points upward at these corner positions: UFR, UFL. 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: L R; R: B F; B: U U; L: F B. The letters identify colors by their reference faces.
Execute the algorithm
F R U' R' U R U R' U R U' R' F'
The opening is F R U'; the final segment is U' R' F'. This version contains 13 face, wide, or slice turns and no whole-puzzle rotations.