4x4x4 Edges

REMEMBER: Before starting any algorithm, make sure that the front (dark grey) face is facing you and the top layer is on the top.

The aim of this section is to take you from this

to this

completing the edges.

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Pairing the Edges

The first part of this process, as with the centres, is more about seeing what is happening rather than learning algorithms.

You can safely rotate any face to create a starting configuration.

Front face

For the purpose of this exercise we will use the red and green edges.  You need to place a matching colour pair on different layers but on the same face of the cube in the configuration displayed here on the right.  Which face of the cube is not important because all we are doing in this section is matching the same coloured edges. If they are on the same layer as displayed on the left you can use either of the two algorithms below to place them on different layers as displayed on the right.

Front face

Once you have the two matching edge elements in place you will need an unmatched pair on the up face on the side that has the lower layer element of the pair you are about to match.

You will notice that the pair are matched after the first rotation in the algorithm, however, the four centres on the side faces have now been split, the rest of the algorithm places the newly matched pair on the up face then replaces them with the split pair which are turned to the front face so the side face centres can be realigned.
 

Up face Front face (Uu) L' U' L (Uu)' Up both Clockwise Left face Anti-clock Up face Anti-clock Left face Clockwise Up both Anti-clock

Up face Front face (Uu)' R U R' (Uu) Up both Anti-clock Right face Clockwise Up face Clockwise Right face Anti-clock Up both Clockwise

Continue this process until all the edge pairs bar two are matched.

You might be lucky when you have finish pairing the third last pair with the final two pairs being matched when the centres are realigned, however, this is less likely than still having to match them.

The problem is that we no longer have a third unmatched pair to realign the centres with.  So you will need to learn the next algorithm to pair the last two unpaired edge sets.

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When the last two pairs are not matched.

This  and the two following algorithms have been placed on the page 4x4x4 Disparity Algorithms for quick reference in the future.

When you still have to solve the last two edge elements you do not have a third set to reset the centres with.

The last pair to be solved are placed on ether side of the front face.  For the edges to be paired  should be on the same layer i.e. they should have the same colour on the front face.  If they are not use either of the first two algorithms on this page.

You now have a 3x3x3 cube, however you may still have parity problems.

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Disparity Algorithms

Cross only has 3 of the 4 bars

The edges you want to flip should be on the top of the front face.

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Solved but for the opposite or adjacent edges in the wrong position.

This algorithm solves the cube for Fig.1 and resets the layer to a 3x3x3 solvable configuration for Fig2.  In each case an incorrectly positioned pair of edges must be at the top of the front face with a correctly positioned pair at the top of right face.