R U S’ (R’ U R) S R’
[setup: (R U’ R) U2 (F R’ F’ R) U2]
Four months! It’s been four full months since my last video/post. Totally unlike me. Busy is an understatement. It’s finally time to come for air momentarily with a tutorial I’ve planned for a long time.
This one relates to F2L 36, a case that I’ve never liked. The standard alg —
U2 (R' F R F') U2 (R U R') — isn’t terribly slow. Nor is it very smooth or fluid. (My older video on that version.) I’ve come to prefer a “tricked out” variant that comes by way of Teller West — and, no surprise, it’s based around the S slice.
Here’s an in-depth tutorial comparing the standard alg to the S slice variant, showing my finger-tricks (very different than Teller’s), and vindicating the standard alg for certain cases:
(cube: Maru CX-3, partially un-stickered))
Like most S-based algs, this one succeeds or fails on finding a fluid, effortless way to finger-trick the slice. I couldn’t manage it the way Teller does. But once I “made it my own” — my recurring advice to cubers of all levels — the alg came together quickly. I push the S’ right-to-left across the top using my index finger, which is naturally on the right side of that edge after the R U; I pull the S left-to-right across the top after the R’ U R lands my index finger to the left of the edge. Mechanically, it all makes sense. But timing is everything.
I’m fascinated by how this algorithm can be deconstructed into component parts to help explain it’s mechanics:
R’ U R
The first “level” in blue is a standard corner insert. Sandwiched between is a series of self-reversing S slices at the next “level” in red, and between those a series of self-reversing R moves (with the critical U smack in the middle). Huh? Basically, it’s a corner insert. But, just before the final R’, the S’ knocks out an edge, the R’ U R brings around the replacement (previously stuck F2L edge). The S flips that edge while pairing it with the corner. When the corner finally inserts, it brings the edge with it. Pretty neat.
Once understood as an expansion of the simple R U R’ insert, it becomes obvious why the S version works only when the flipped edge is in its own slot. If the flipped edge is in another slot, you need to use another alg — as emphasized at the end of the video.
It was fun to spend time on this one. Busy I remain, but hopefully it won’t take another four months to pump out the next post.