EO Line is ZZ's signature opening: flip every "bad" edge, then place the two bottom line edges — and the whole rest of the solve needs no F or B turns and no rotations. Spotting bad edges: check the sticker facing up/down (top and bottom edges) or front/back (middle edges). White or yellow there = good. Red or orange = bad. Green or blue = look at the edge's other sticker: white/yellow makes it bad, red/orange makes it good. Gray stickers in the pictures don't matter.
Flipping the bad edges
Four bad, all on front
F
Four bad, all on back
B
Two bad edges
F R' F'
Eight bad edges
F B
Placing the line
Line edges beside home
D'
Line edges on top
R2 L2 D'
Tips
- Bad edges always come in even numbers — count them the moment inspection starts.
- An F or B turn flips exactly the four edges on that face: gathering four bad edges onto one face fixes all of them in a single move.
- The line edges are already oriented after EO, so they drop in with side and bottom turns only — R2/L2 down, then align with D.
- This is the hardest step of ZZ and the biggest payoff: everything after it is rotationless.