PCMS
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PCMS (pairs, CLL, M and S slices) is an advanced method for speedsolving using columns first, designed by Kenneth Gustavsson in late 2008. The method compromises between easy look ahead and low move count (slice metric), and the result is 'decent' for both parts.
Steps:
- Columns
- Slices
Pairs:
The move count is dependendant on how well the first step is solved, if you add some extra look ahead and pair up more than one pair before you start to place them you can get as low as 10 turns for all four pairs at times. But!, the number of moves is not that important if you are speedsolving, the gripping while solving the pairs is the part where you can gain speed in this step, rather place a pair using U Rw U R' than (y') R' U R, that to avoid cube orientations. If you are speeding 15-17 turns is not uncommon, rather normal.
Pairing up is done a bit diffrent from what is used in Fridrich F2L, first find a pair, preferably one where the corner is unoriented in the U-layer and the edge is in the D-layer. If the edge is not there, then one in the U-layer is a second choise because it is easy to place in D using a single slice move. Orient the cube so that the edge is in FD or BD position, move the corner to position using a U move and then the pair is built using the M-slice. For the pairs where the corner or the edge is in bad position you have to do some setup turns to fix that, or simply use the CFOP alg for the same pair.
Example:
Scramble:
| 1.
L2 B F U2 F' L2 B' D F' U2 R D2 L F2 L' D' B2 F U2 |
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- p1; pieces are good, just do M2 to pair up and (z) to place.
- p2; because only one pair is solved here we can do the next from bottom and up like this: U L2 to pair and R' U (x) to place it.
- p3; nice corner, edge in U-layer so setup that one first using (y) M' then U M2 to pair up and U2 B' to place it (temporarly move the B-side to U before the B turn).
- p4; both pieces in position so: (y) U2 M2 to pair up and U R' U2 R to place.
16 moves not counting puzzle rotations, pretty normal.
CMSLL:
CMSLL is pretty much the same as CLL for 2x2x2 (or CF) but in some cases you need to use double layer turns to preserve the pairs, for example R U' R' U' F' U F becomes R U' Rw' U' F' U F. In cases where that does not work any alg optimal for CMLL will do fine but with the advantage that you don't have to AUF the case so it fits with the empty M-slice, here the S-slice is equally good to use.
Algs and all cases you can find at the CxLL pages.
Example:
If we continue from the example for the pairs then this case is Sune :P
- (y2) R U R' U R U2 R'
Slices:
The first part of the second half of the solve is all intuitive, you pair one first layer edge with it's centre and then place it into position. After some parctice this is so easy you can say it is at noob level, no thinking required. It is possible to create more advanced methods than this and use algs for some parts but that is not a good idea, it would only kill the easiness and speed for this part of the solve.
Example:
(Continued from above)
- 1p; U' M' to pair (y) M' to place.
- 2p; paired! M' U2 M to place.
- 3p; paired again, (y') U2 M' to place.
Note that you may solve the third pair before the second using only one move, that would save one U2 but add one puzzle rotation. I usally solve the edge opposite to the first as the second one just to save on rotations, I think that it is faster on average, aspecially if you look for that edge while solving the first one (if it is stuck in D then try to find one edge that goes to the side in U instead).
L5E: (dunno what name I used at first but it will be L5E from here, that to stick to cubing vocabulary standards =)
Example:
(Continued from above)
- U' M' U' M U M' U' M to orient and place FD edge.
- U-PLL
See L5E for description and algs.
You only need five algs for orientation but it is a good idea to add as many as possible that also solves the FD edge, this has two reasons, first is that EPLL is faster to recognise than the full L5E permutations (the 5-cycles are particulary slow), the second reason is that EPLL skips 1:12 times, for five oriented edges that number is 1:60.
