ZZ-CT was created with the intention of fixing everything wrong with ZBLL, and to create the first feasible LL-Skip method under 200 algorithms. Several months of brainstorming and evolution led to ZZ-CT, as reported herein:
The core fundamental concept is the orientation of corners before reaching last layer.
By abusing rotational symmetry probabilities of oriented pieces, it was observed that LL Skip algorithm count could be reduced by at least an order of magnitude or more. This pre-orientation also allowed for simple and obvious recognition of permutation.
The first incarnation of this method was one which oriented all corners during the completion of the third slot, and then forced LL skip (~800-1000 algorithms).
ZZ-HW was the next big improvement, which oriented all corners and inserted the corner in the fourth slot, followed by forced LL skip(~200 algorithms). However, this method was limited by algorithm ergonomics, since diagonal corner swap and edge insertion algorithms are too long and are not sufficiently ergonomic for competitive speedsolving purposes.
By maintaining the same concept and algorithms, but instead inserting an edge instead of a corner. This ergonomic barrier was not only overcome, but completely annihilated in comparison. The overall quality and movecount was dramatically enhanced due to the properties of corner permutation.
This property serendipitously yielded very surprisingly short, ergonomic algorithms such as x' (R' U R U')*3 and R2 U2 R2 U' R2 U' R2. Additionally, an entire 12 case RUD subset was observed to be completely regripless.
WARNING: Some of this information may be wrong. I've compiled hundreds off algorithms together and there is a good chance that I messed something up.
The four steps of ZZ-CT is: EOLine, ZZF2L, TSLE, and TTLL
Make a eoline just like classic ZZ.
Do ZZF2L up to F2L-1.
You can either always leave FR as your last slot or just learn how to mirror your TSLE algs.
Insert the last F2L edge while simultaneously orienting all of the corners.