Mehta-MH

From Speedsolving.com Wiki
Revision as of 16:54, 7 October 2021 by Matthew H (talk | contribs)
Mehta-MH method
Mehta-MH icon.png
Information about the method
Proposer(s): Matthew Hinton
Proposed: 2021
Alt Names:
Variants:
No. Steps: 6-7
No. Algs: 6-80
Avg Moves:
Purpose(s):

Mehta-MH is a speedsolving method designed for big cubes. It was proposed by Matthew Hinton as a way of applying the Mehta method to higher order puzzles. Mehta-MH solves blocks in pseudo layers in similar fashion to OBLBL, by connecting rows of centre pieces.

Steps

  1. First 2 Centres (F2C): Solve two opposite centers in the U and D layers (same as Yau F2C).
  2. First Block (FB): While keeping the solved centers on U and D, build a 1 by n-1 by n block like in Mehta but with more pieces.
  3. Pseudo Block Layers: Solve pseudo (non-matching) layer(s) of three rows of centre pieces and two unpaired edge pieces on top of the FB, until only one layer and the R-face of centre pieces remain unconnected.
  4. Last Block Layer: Intuitively connect the remaining pseudo layer and R-face centre rows. This requires some skill and a good knowledge of centre commutators on cubes larger than 4x4x4. On 6x6x6 and up, solve only the corners of the F- and R-face centres and then use algorithm to permute the cedges (edge-like pieces of the centres).
  5. Pair and Orient U/D Edges: Use simple edge pairing to solve two pairs of edge pieces at a time until all the U- and D-layer edges have been connected. Use triggers to orient these edges as you pair them. It may be useful to do a y rotation before this step so you can use the <RUFL> moveset for insertions.
  6. 3x3x3 Stage: Rotate all the layers so that the centres are solved. You have now reduced the cube to the 3x3x3 EO-Belt state in Mehta. Use any Mehta path to complete the solve. You may have permutation parity on even order cubes, which can be solved with one algorithm or you can learn the extra PLL/L5EP parity algsets.

Naming

The Mehta-MH naming convention has the following forms:

  • Mehta-MH{N} means the method and algorithms/commutators for a cube of order N (e.g. Mehta-MH4 is for the 4x4x4)
  • Mehta-MH+ is the method for cubes larger than 7x7x7, including 8x8x8 centre comms. This is the most advanced variation.
  • Mehta-MHX is used to describe the method in general or the knowledge of all the variations.

Pros + Cons

Pros

  • Few or no rotations.
  • Better lookahead to edge pairing and 3x3x3 stage than Reduction.
  • Reduces to the advanced Mehta method
    • 3 algorithmic steps instead of 2, allowing for higher TPS in 3x3x3 stage.
    • Ergonomics: About 40% of the 3x3x3 stage is <RUD> gen. 17% is always <MU> or <RU> gen.
  • ABFs get easier on large puzzles.
  • Edges in edge pairing stage all have U- or D-face stickers for easy recognition
  • No oriental (OLL) parity

Cons

  • Bad lookahead in pseudo blockbuilding, specifically recognizing the correct 'wing' edge pieces.
  • Can’t use freeslice, and two-pair-at-a-time edge pairing is inefficient.
  • High algorithm count for a big cube method.
  • Some 6CP and APDR algorithms have many R2 moves in a row. However, an advanced solver would be able to option-select to avoid bad cases.
  • Adjusting both faces at the end has a higher chance to get a +2 or DNF.
  • Transition between algorithmic steps is difficult to master.


See also

External links