3x3 · ZBLL
3x3 ZBLL U 21 algorithm
3x3 ZBLL U 21 algorithm: 14 turns, opening with R2 D' R. Case recognition, the complete sequence, and practical execution notes.
Solve the entire last layer in one sequence when its edges are already oriented.
ZBLL U 21 belongs to the U2 group in ZBLL.
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 top row left to right when facing that side gives F: F B R; R: B F L; B: U R U; L: F L L. The letters identify colors by their reference faces.
Execute the algorithm
R2 D' R U2 R' U' D R' U' R2 U R U R2
The opening is R2 D' R; the final segment is R U R2. This version contains 14 face, wide, or slice turns and no whole-puzzle rotations.