Keyhole Method

Keyhole is an efficient method for inserting mid-layer edges in the 3x3x3 LBL method. Its a slight advancement on the basic LBL method, because it requires fewer moves, as. well as more intuition.

Basic Idea

After the bottom layer cross, only three bottom layer corners are solved. The final corner is reserved as the keyhole to be used in solving the mid layer edges efficiently. To insert a mid layer edge using the keyhole:

• First position the mid-layer edge in the U-layer such that it is above the centre matching the edge's up-facing colour.
• Now position the bottom layer so that the unsolved corner is directly below the mid-layer edge's position.
• Now execute one of R U' R' or F U F' to insert the edge.