ZZ-CT

ZZ-CT method Information about the method Proposer(s): Chris Tran Proposed: 2015 Alt Names: Variants: No. Steps: 4 (EOLine, F2L-1, TSLE, TTLL) No. Algs: 200 Avg Moves: 40-50 Purpose(s): Speedsolving

ZZ-CT is a 3x3 method proposed by Chris Tran. It is a variant of the ZZ Method with a unique 2 look LSLL, divided into TSLE and TTLL.

TSLE inserts the last edge whilst orienting all corners, and all states can be carried out with at most three R U R', R U' R' or R U2 R' triggers. Many of the TSLE insertions are the same as the traditional F2L algorithm, and has a much lower move count than other last slot methods since it ignores permutation of the corners and edges except UF.

TTLL solves everything all at once with 48 cases, and is named after Chris Tran (who created the method) and Blake Thompson (who generated a significant portion of the algorithms).

Steps

1. EOLine
2. F2L-1
3. Insert last edge and orient corners. (108 cases) (TSLE, Tran Style Last Edge)
4. Solve everything else. (72 cases) (TTLL, Tran-Thompson LL)

History and Advantages

The original goal of ZZ-CT was to fix all the shortcomings of ZZ-A (ZZ+ZBLL), and to present the first feasible and competitive 2-Look LSLL method under 200 algorithms. Several months of brainstorming and evolution led to ZZ-CT.

The first incarnation of this method was one which oriented all edges and corners during the completion of the third slot, and then using an LL skip algorithm to solve everything else (~800-1000 algorithms). ZZ-HW was the next improvement, which oriented all corners and inserted the corner in the last slot followed by the LL skip algorithm (~200 algorithms), but was limited by algorithm ergonomics. Diagonal corner swap and edge insertion algorithms are too long and are not sufficiently ergonomic for competitive speedsolving purposes.

However, by inserting an edge instead of a corner, this hindrance could be ignored, and novel beneficial attributes were serendipitously discovered, as reported herein.

When compared with ZBLL, ZZ-CT solves the issues of large algorithm count, recognition, statistical hindrances, practise requirement, and steep learning curve by having a significantly lower algorithm count, equivalent amount of looks, obvious colour blocks (PLL recognition), and significantly better statistics.

Statistically, ZZ-CT leads to good single times due to the following attributes:

1. PLL occurs 20% of the time. Leading to a well known algorithm that most cubers already know.
2. True LL skip occurs approximately 0.27% of the time(1 out of 360 solves), as compared with 0.0064% in CFOP(1 out of 15552 solves), and 0.051% in ZZ(1 out of 1944 solves). Which means that the probability is increased by orders of magnitude.
3. 2-Gen TTLL occurs 26% of the time, as compared to 15% chance for a 2-gen ZBLL and 1.8% chance for a 2-gen LL in CFOP.
4. TTLL cases individually occur much more often, with similar percentages as OLL. In comparison, the statistics for ZBLL cases means that some cases will only pop up every few days during solves, meaning that it requires much less practice to execute TTLL than ZBLL.

Disadvantages:

You have to use ZZ.

Example Solve:

Scramble: R2 F2 R' U2 R2 B2 U2 R' B2 D2 U' L2 F L' R2 F' U2 R2 U F'

EOLine: X' D' L' F L U R2 D'

F2L-1: R U' R' U R' U2 L U2 L U L R' U R D R U' R' D' U

TSLE: R U2 R' U' R U2 R'

TTLL: y' U R' U R U' R' U2 R U R' U' R