Reducing to the group of retaining 4 pairs

Foreword

Now to make the 4th pair, it is one of the two pairs in the figure below. The X symbol is the 3 pairs that have been prepared before.

All the rotations of this step only rotate the R, U faces, and do not destroy the 3 pairs that have been completed in the previous steps.

Fig. 1
Fig. 2

Go to the Relay Station

When combine the 4th pair, all the first 3 pairs that have been completed are turned to the same layer first, and the two pairs that are connected to each other must be completely separated when rotating the other face. The shape is as shown in Figure 3 below. . The first 3 pairs that have been completed can be considered the same. The position of the corner to be combined with the new pair will therefore be fixed at the colored position in Figure 3. The shape of the old pair does not change before and after results of the next moves.

For convenience of explanation below,
the Relay Station M is the X symbol position in Fig. 4, and the Relay Station N is the X symbol position in Fig. 5.

Fig. 3
Relay Station M
Fig. 4
Relay Station N
Fig. 5
Go to the Relay Station M
Move 1
Move 2
Move 3
Go to the Relay Station N
Move 4
Move 5

The edge on the Relay Station combine with the corner of new pair

On the corner where the new pair is to be combined, the stiker of the same color as the edge to be combined is the stiker with the X symbol in Fig. 6 below, and must be combined with the edge on the Relay Station N.
Fig. 6
Move 6
On the corner where the new pair is to be combined, the stiker of the same color as the side block to be combined is the stiker with the X symbol in Fig. 7 below, and must be combined with the edge on the Relay Station M.
Fig. 7
Move 7

Example

In the following Example 1, the color of the edge of the new pair can be   . The stikers of the two colors on the corner where the new pair is to be combined are as shown in Fig. 6, so turn this edge to Relay Station N by Move 2, 4 first, then do Move 6 to combine the new pair
Example 1
  • Turn 1~7 is Move 2
  • Turn 7~14 is Move 4
  • Turn 15~16 is Move 6
In the following example 2, the color of the edge of the new pair can be   . The stikers of the two colors on the corner where the new pair is to be combined are as shown in Fig. 7, so turn this edge to Relay Station M by Move 3 first, then do Move 7 to combine new pair
Example 2
  • Turn 1~10 is Move 3
  • Turn 11~15 is Move 7

next: Reducing to the group of retaining 3 pairs and 1 1x2x2 block The RUP Method

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