The Professor's Cube

VI. Solve the Middle Inner Edges

This has the same steps as the previous sections; move an edge from the bottom, knock it down or invert it. It may be scary at first. When solving any of the middle edges, the top side gets scrambled temporaily; but after the moves are over with the top side is intact again, with another middle edge in place to boot!

Chances are, you have inner-edges on the bottom layer that need to be moved up to the equator. Rotate the bottom layer to set the edge piece in the starting position. Before doing any moves, you must make sure that the patterns are just like the diagrams below. The colors may be different, but the pattern must be the same. Notice how the edge piece (on the bottom, in the starting position) looks like it's mismatched with the front side.

~~~~ Move Up: ~~~~


B2 N- B- R-
B+ N+ B- R+


B2 N- B+ L-
B- N+ B+ L+

A middle inner-edge piece could already be in the equator, but in the wrong spot. Use the sequence below to knock it down to the bottom layer. You can move it back to its proper place later, by using one the sequences above.

~~~~ Knock Down: ~~~~


N- B- R- B+
N+ B- R+

In case you haven't noticed, this sequence looks very similar to one of the "move-up" sequences. In reality, all you are doing is moving up an edge from the bottom, which in turn knocks down the target edge from the equator.

Hint: Use the "Knock-Down" sequence only as a LAST RESORT. Almost all the time, that edge can be knocked down to the bottom layer later anyway, when you are merely doing a "Move-Up" sequence with another middle-edge piece.

A middle inner-edge piece could already be in the equator and at the correct spot, but inverted. Use this move to flip it around:

~~~~ Invert: ~~~~


N- B- R- B+
N+ B- R+ B-
N- B- R- B+
N+ B- R+

The bad news is, at 15 moves that this sequence is very long. The good news is that you don't have to memorize it! This sequence is actually a combination of the "knock-down" sequence, followed by one of the "move-up" sequences. So if you don't want to memorize this, knock down the edge from the equator (by using the "knock-down" sequence), and then turn the bottom layer until that edge appears on the bottom-front. After that, move the edge up using the proper "move-up" sequence.

Q: Why do I have to solve the inner-edges last while solving the three layers of the EQUATOR?

A: You don't. You can solve the inner-edges first before doing the outer-edges if you want. You can even alternate (inner-edge, outer-edge, etc.) the solution steps if you want. The moves for solving the middle edges do not interfere with each other; so you can choose to solve the cubelets a column at a time or even layer by layer. However, You MUST finish all the middle edges (inner & outer) before solving the...
Bottom Corners.

@ Notation / Top Face
@ Top Corners @ Top Outer-Edges @ Top Inner-Edges
@ Middle Outer-Edges @ Middle Inner-Edges
@ Bottom Corners @ Bottom Outer-Edges @ Bottom Inner-Edges
@ Middle & Bottom Faces

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