User:Dave3457/sandbox/Details of 5.66 World record

In the Melbourne Winter Open of 2011 Feliks Zemdegs completed a world record, 5.66 second solve of the Rubik's cube.


 Initial position

To the right was the initial position of the cube. It is fair to say that this solve was a bit shorter than his others, in part because he was initially given 3 edges and a corner on the first layer. This resulted in him having six pieces solved after 8 moves. That being said, while 8 moves is low, it is not that untypical. For example in a 7.94 second solve in his 8.52 sec WR average he completed those six pieces in 7 moves while getting only one “gimme”. It is worth noting that the first few pieces are the easiest and quickest to solve because you don’t have to worry about the rest of the cube and you have lots of time to think about how you are going to solve them before the clock starts. Comparing this solve with his others below, it does not seem to have been that great a factor. If you compare this solve with his other solves in the competition, with which he won world record for average solve time, it is clear he did not save too much. Those solves are reconstructed below.


Initial position  Completion of X Cross stage.

His first step was to finish the cross of edge pieces, and simultaneously complete the first of four F2L corner pairs. A F2L corner pair is a matching corner and edge piece which fits into one of the corners of the cross. Refer to the image. Completing the cross and forming the first F2L at the same time is called doing an extended cross.

The below link will take you to an applet that will take you through the first stage of the solve. Rather than click the play button of the applet, it is suggested that you instead repeatedly click the forward button that is in the lower right corner of the player. Extended Cross

Front view Back view

The next three stages involved inserting the other three corner edge pairs. The link below will take you to an applet that runs through the three stages. The applet begins in the position on the left. The corner pair on the far right is solved first, then the middle one and then the leftward one.

2nd F2L & 3rd F2L & 4th F2L

Interestingly, when solving the second corner pair Feliks applied the combo..R U R’ U U R U’ R’ which contains two identical quarter rotations in a row. This being in the middle of a combination, he could have simply applied a single half rotation. It can be estimated that this cost him 1/5th of a second since in the video, between these two moves, the cube is basically stationary for 5 full frames . [Slow motion YouTube video with the moves tracked]

The next step in his chosen method was to first orientate the pieces in the last layer. After orientation the position the four corner pieces where also solved. Feliks may have specifically selected an algorithm that would also position the corner pieces at the same time, or he may have gotten a “gimme”.

OLL

The last step was to position the final 3 edge pieces.  

PLL

Below is a break down of the solve.<Ref> Reconstruction by Nick Evdokimov / amostay2004. U2>U U corrected</ref>

Scramble: D2 L2 D2 R2 B' R2 F2 L2 U2 F' R2 U B D U' L' U F' U2 L2 F'

X-Cross: y' R U' R d R' U R D  ; Here he solved the cross and the first F2L corner pair simultaneously. 2nd F2L: y' U' R' U R U' R' U' R  ; Inserted the second corner pair. 3rd F2L: R U R' U U R U' R'  ;Inserted the third corner pair. 4th F2L: L' U L U L' U' L  ;Inserted the fourth corner pair.

OLL: U' R' U' F U R U' R' F' R  ; Oriented the pieces in the last layer and positioned the four corners. PLL: R' U R' U' R' U' R' U R U R2 U  ; Positioned the last three edges.

53 moves, Time 5.66 sec, 9.4 turns/sec

Below is an applet of the entire solve without any extra inserted rotations. In this applet, Feliks would have been looking at the cube from the left. For those unfamiliar with speed solving, it is interesting to note that a cuber selects the algorithms that can be executed the quickest, these are not necessarily the algorithms that require the fewest turns. A cuber will pick the longer one if it can be executed more quickly and those algorithms are usually the ones that involve manipulating only 2 sides. They are called 2-gens. In the applet you will notice that Feliks generally only manipulates two sides in combination with each other.

R U' R d R' U R D y' U' R' U R U' R' U' R R U R' U U R U' R' L' U L U L' U' L U' R' U' F U R U' R' F' R R' U R' U' R' U' R' U R U R2 U This applet is identical with the exceptions that the cube is given a 360degree rotation between stages.


Fewest moves solution: R B U2 R' F U' F' U2 F' D R2 D' B2 D L U' (16) <ref>Thead sjont</ref>

In that same competition Feliks set several world records. Below are the reconstructions <ref>Member qqwref at this forum thread</ref> of the five solves with which he set a world record of 7.64 sec using an average of three solves. Note that the longest and shortest times are not counted in the average.

1. 7.03 sec
scramble: R2 U2 F2 R2 B2 R' F R U' B' F' D B L2 F' R' U' B' R'
inspection: y
cross: R' U R' F D2 R D
F2L1: R' U R
F2L2: y' U d R U' R2' U R
F2L3: d' R' U' R
F2L4: y2' U' R' U R U R' U' R
OLL: U F R U R' U' F'
PLL: U R' U' R y R2 u R' U R U' R u' R2'
Feliks Zemdegs Melbourne Winter Open 2011 3x3x3 1. 7.03 sec
Feliks Zemdegs Melbourne Winter Open 2011 3x3x3 1. 7.03 sec -With 360o turns


2. 8.11 sec
scramble: F2 U2 B L2 R' B' L B2 U B' F L R F' U B D2 U'
inspection: z
cross: U' D r U' r' x'
F2L1: U' R' U R2 U' R'
F2L2: y2 R' U' R U R' U R U2' R' U R
F2L3: y' U2' R' U2 R U2' R' U R
F2L4: U' R U R'
OLL: U U' F R U R' U' F' f R U R' U' f'
PLL: y' x' R2 D2 R' U' R D2 R' U R'
Feliks Zemdegs Melbourne Winter Open 2011 3x3x3 2. 8.11 sec
Feliks Zemdegs Melbourne Winter Open 2011 3x3x3 2. 8.11 sec -With 360o turns


3. (8.36) sec
scramble: D2 L2 R2 B F2 R2 U L' F' R D U' L D F2 U2 F' D2 F'
cross: U' l' D' L D' R2
F2L1: d' R U' R' U' R U' R' U R U' R'
F2L2: U L' U' L U' R' U' R
F2L3: y2' R U' R' U R U' R' U2 R U' R'
F2L4: R' U R U' R' U' R
OLL: R' U' R U' R' U R U x' R U' l' B
PLL: U R U' R' U' R U R D R' U' R D' R' U2 R'
Feliks Zemdegs Melbourne Winter Open 2011 3x3x3 3. (8.36) sec
Feliks Zemdegs Melbourne Winter Open 2011 3x3x3 3. (8.36) sec -With 360o turns

4. (5.66) <ref>(reconstruction by Nick Evdokimov and amostay2004) U2>U U corrected </ref>
scramble: D2 L2 D2 R2 B' R2 F2 L2 U2 F' R2 U B D U' L' U F' U2 L2 F'
xcross: y' R U' R d R' U R D
F2L2: y' U' R' U R U' R' U' R
F2L3: R U R' U U R U' R'
F2L4: L' U L U L' U' L
OLL: U' R' U' F U R U' R' F' R
PLL: R' U R' U' R' U' R' U R U R2 U
53 moves, 9.4 turns/sec Feliks Zemdegs Melbourne Winter Open 2011 3x3x3 4. (5.66)
Feliks Zemdegs Melbourne Winter Open 2011 3x3x3 4. (5.66) -With 360o turns


5. 7.78 sec
scramble: L B2 F2 D2 R B' D U' L' D2 F2 D' F2 R D2 U' L B' R2
inspection: x2 y
cross: R2' F D2 U R' F
F2L1: y R U' R'
F2L2: U' R' U' R U' R' U R
F2L3: U y' U2' L' U L U' y' R U' R'
F2L4: R' U R U' R' U2 R U' R' U R
OLL: U' R' U' R U' R' U2 R F R U R' U' F'
PLL: R' U2' R U R' z R2 U R' D R U'
Feliks Zemdegs Melbourne Winter Open 2011 3x3x3 5. 7.78 sec
Feliks Zemdegs Melbourne Winter Open 2011 3x3x3 5. 7.78 sec -With 360o turns


For all of Feliks's 3x3x3 WRs reconstructed refer to qqwref’s thread