26 HTM Domino Reduction Solve by Tomoaki Okayama

Scramble (fmc.mustcube.net #310): U’ D2 L R’ F2 R B D’ F’ B2 U’ D’ F’ R2 L2 F U B’ D2 U’ B’ L F2 U R D’ B F R’ U’
Solution: L R2 F’ D’ F2 B2 R’ U L U’ R2 U L U B2 D B2 U F2 R2 U R2 U F2 U’ L2 (26 HTM)

Explanation:
Pre-scramble: L2

1) getting into <U,D,L,R,F2,B2> group

L R2 F’

2) getting into <U,D,L2,R2,F2,B2> group
2a) edges

D’ F2 B2 R’

2b) corners

U L U’ R2 U L’

3) domino-solve

2x2x2 block: L2 U B2 D B2
2x2x3 block: U F2 U
F2L minus 1 slot: F2
Solve all: F2 U’ R2 U R2 U F2 U’
Correction: L2

Comment:

Guus Razoux Schultz said:

Hi Okayama,
Very smart solve! How long did you need to find this?
Yes, this was a very hard scramble for 1-hour solve. I had a 35-move-backup-solve but I thought it wasn’t worth posting. Now I see the best 1-hour solve was 36 moves. What was your 1-hour solution?

With pre-moves U2 L2 you can find nice starts but all left rubbish, also for NISS!

Gus

Tomoaki Okayama’s answer:

Hi Guus,

Curious about the length of time? Maybe not only you.

I spent a long time actually, a few hours. Most of the times were spent on investigating the step 3).
So I don’t think this approach can be used in an official competition, at least for me.

In 1-hour solve of #310, I didn’t have any full solution (DNF).
Here are some of my tries:

1st 2x2x1 block: F’ D2 F2 D2
2nd 2x2x1 block: B2 L2 U2
Pseudo 2x2x3 block: L’ U R’
F2L minus 1 slot: F’ U’ F2 U F L’
Finish F2L L’ B L B’
Pair 3-cycle: L U L’ U’ L’ B L B’

first try, almost linear solve, which leaves 3 corners with 27 HTM.
I should complete this skeleton as a backup solution.

Another interesting start for the inverse scramble:

2x2x2 block: L’ U2 D2 R’ L’ D
2x2x3 block: U2 F U2 R2
F2L minus 1 slot: L’ U L U2

I couldn’t find a good continuation in 1-hour. But just now, I found the following continuation:

All but 3 corners: U2 F’ U F’ U2 F U F’ U F2 U2

Not special, 23-moves skeleton. I hope I could find this skeleton in 1-hour…

Original post; comment taken from here and here.

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