Keyhole First Two Layers
From Speedsolving.com Wiki
Keyhole First Two Layers or keyhole F2L is a method that solves, normally, the first two bottom layers of the 3x3x3 cube.
You start, like in normal LBL from a cross, then you fill in three of the first layer corners. From that point you solve three of the middle layer edges using the empty corner position as the keyhole. After three corners and edges are solved you compleate F2L by first solveng the last corner and finaly the last edge is solved using the normal LBL algorithm: R U R' U' F' U' F or the mirror F' U' F U R U R' depending on the current orientation of the edge.