K4
From Speedsolving.com Wiki

K4, short for Kirjava's 4x4x4 Method, mixes Reduction, Blockbuilding, Edge pairing and Direct Solving techniques to produce a method that can quickly and efficiently solve a 4x4x4 (Revenge) cube.
It should be noted that while K4 is designed specifically for the 4x4x4 cube, it can be applied to any size of cube. Modifications can be made to make it friendlier to solve on the bigger (>=5x5x5) cubes.
Contents
Overview
The K4 Method consists of 7 steps;
 Two opposite centres
 Blockbuild a 1x3x4 block
 Complete the last four centres
 Complete the first layer
 Rotationless F3L
 CLL
 3 look ELL
Pros
Small number of rotations required
Efficient movecount
Extremely good F3L lookahead
Cons
Commutators are required for a good understanding of the method
ELL can be difficult for beginners to grasp