Solving Big Cubes by Logic
4.h. Solving the center edges of the remaining borders
This step is only performed if the cube is odd. It allows solving all center edges of the remaining borders. Furthermore, it avoids a kind of parity error that can occur at the end.
The method used here is exactly the one already known for the case of solving the last edges of the 3x3x3. The “free column” is used to make the swaps and the correct orientation of the central edges in the last layer. When these are solved the central edge of the “free column” will be also solved. For more details see the guide to solve the 3x3x3 by logic.