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kinch2002

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Scramble from Northern Irish Open 2013: U' B2 D2 F2 L2 D R2 F2 D' L2 B' D2 R' F D' R2 U2 L U F

My solution: 26 moves (=NR) L2 F' L2 U R' L' F U B' D' B' U B D U2 L2 U B' U B U2 B' R B' R' B2

I'm not too proud of this joint NR (with myself and Rob Yau) because although it's decent, I was expecting a 29 mover or so from the skeleton, and the 5 move cancellation is basically luck and not skill. Also, no NISS or premoves :(

2x2x2: L2 F' L2 U R' L' F (The L' just makes the extension to 2x2x3 easier)
2x2x3: U B'
F2L-1: B' U B U2 L2
Some EO: U B' U B
F2L and edges leaving 3 corners: U2 B' R B' R' B2
Skeleton: L2 F' L2 U R' L' F U B2 * U B U2 L2 U B' U B U2 B' R B' R' B2 (23)
Insert B D' B' U B D B' U' at * to cancel 5 moves
Final solution: L2 F' L2 U R' L' F U B' D' B' U B D U2 L2 U B' U B U2 B' R B' R' B2


33, 33, 32, 29, 28, (26), 27, (DNF), 31, 27, 28, 26 = 29.4 avg12
I wish you lots of fun rolling this. :)
Thank you. Hopefully I can make it into the 28s :)
 

Sebastien

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On the hardest scramble: F U' F2 D' B U R' F' L D' R' U' L U B' D2 R' F U2 D2

[Brief History] Full solutions for the scramble by human beings in this thread:
  1. 35 HTM by Conrad (maybe first try, in 1-hour?)
  2. 34 HTM by me (in 1-hour) and shorten Conrad's solution to 32 HTM (after 1-hour)
  3. Another 32 HTM solution by me (after 1-hour)
  4. 31 HTM by Guus (in 1-hour)

Then 30 HTM solution by me:
Solution: F' R D2 R2 B' D B U F' U' B' D2 U' L U' R B' L' B R' B' L R B R' U2 B R' U R

[...]

Keep trying! :D

I wanted to challenge myself and asked Tomoaki for hard scrambles he had listed, so I tried this scramble for the first time today. The result makes me pretty happy! :)

My solution (within 1 hour):
Pseudo 2x2x3 on Inverse: F' R B D B L' B' U' F D F'
switch and L5C: D2 R' B' R D R2 B' R D

Skeleton: D2 R' B' R D R2 B' R D F D' F' . U B L B' D' * B' R' F

. = F2 U' B2 U F2 U' B2 U
* = D B U' B' D' B U B'

Solution: D2 R' B' R D R2 B' R D F D' F U' B2 U F2 U' B2 U2 B L U' B' D' B U B2 R' F

29 moves!! :)
 

Robert-Y

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Oh my god... I thought no one was trying anymore :p

I occasionally tried to get sub 30 on this scramble but never succeeded. I think my closest was a 30 with a sune for LL. But I might have miscounted.

Congrats Sebastien!
 

Cubenovice

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My solution (within 1 hour):
Pseudo 2x2x3 on Inverse: F' R B D B L' B' U' F D F'
switch and L5C: D2 R' B' R D R2 B' R D

Skeleton: D2 R' B' R D R2 B' R D F D' F' . U B L B' D' * B' R' F

. = F2 U' B2 U F2 U' B2 U
* = D B U' B' D' B U B'

Solution: D2 R' B' R D R2 B' R D F D' F U' B2 U F2 U' B2 U2 B L U' B' D' B U B2 R' F

29 moves!! :)

Congratulations!
I hate that scramble with a vengeance :(
 

guusrs

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I wanted to challenge myself and asked Tomoaki for hard scrambles he had listed, so I tried this scramble for the first time today. The result makes me pretty happy! :)
29 moves!!

Hi Sebastien.

Congratz with your latest awesome competition results.
I will use the scrambles and your solutions for my training.
And also compliments for everyone who had consistantly sub-30 results:
Tomoaki, Daniel, Milan, Erik, Teemu (still cubing?)

29 moves for the hardest scramble is excellent too. I spend several hours on it to get it sub-30 but failed so far.
Now we have to give the hardest scramble a new try. Not for the 1-hour record, Sebastien holds it now, but for the unlimited-time one

My DNF rate at comps (±50%) is just too high to ever get a mean-of-12 average.
But I promise improvement. My weekly online-comps-results give me hope. For example: no one will beat my result in this week 2013-15 FMC!

See ya guys.

Gus
 
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BQ

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Pseudo 2x2x3 on Inverse: F' R B D B L' B' U' F D F'
switch and L5C: D2 R' B' R D R2 B' R D

Skeleton: D2 R' B' R D R2 B' R D F D' F' . U B L B' D' * B' R' F

. = F2 U' B2 U F2 U' B2 U
* = D B U' B' D' B U B'

Solution: D2 R' B' R D R2 B' R D F D' F U' B2 U F2 U' B2 U2 B L U' B' D' B U B2 R' F

29 moves!! :)

Can you share your experience about finding two insertions within one hour?
I just wonder how you found the optimal insertions.
 

okayama

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My hats off to you, Sébastien. I couldn't choose a proper face mark from the list. :) :( :confused: :mad: :p ;) :D :eek: :tu :cool: :eek: :fp

Now I update the history for the hardest scramble (list those who wrote down a full solution in this thread).
Scramble: F U' F2 D' B U R' F' L D' R' U' L U B' D2 R' F U2 D2
  1. 35 HTM by Conrad (maybe first try, within 1-hour?)
  2. 34 HTM by Tomoaki (within 1-hour) and shorten Conrad's solution to 32 HTM (no time limit)
  3. Another 32 HTM solution by Tomoaki (no time limit)
  4. 31 HTM by Guus (within 1-hour)
  5. 30 HTM by Tomoaki (no time limit)
  6. 30 HTM by Attila (no time limit)
  7. 32 HTM by David (no time limit)
  8. 29 HTM by Sébastien (within 1-hour)
If there's any omissions/missings, please let me know the solution.

In addition to the hardest scramble, I would like to share some hard scrambles here (Sébastien said in his post).
  • Dutch Open 2009: R2 D B2 U B2 D B' D' R' U' F' D2 B2 R D L' B' F*
  • by Cielo: L' R2 B2 D2 B2 R' B L' D' U F' L' F2 D' R2 B' U2 R F2 U'*
  • FMC336: F' R U D' L2 F' B' U' B2 F2 L R' U D B2 F L R' B R' B D F2 R' D2 F' B' D U2 R
  • FMC310: 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'
  • FMC307: L' D B' D2 F' B U D' R F' D F' L B' D R' L' D F2 L D B2 F' U' L' R2 B' F L2 R
  • FMC283: U' D2 B U L' B' F2 D2 L R U2 F' R' L2 D U2 F2 B' D' L' B' F2 U R B' F' R' U' B2 F2*
  • FMC280: U' F2 U' D2 B2 U' B' F U' B L' U2 D' L' F2 B D2 B' L' B F R D R2 U R' F' U2 D R2
  • FMC279: U' F' U2 B' L D' U F2 L2 B' U2 F2 B2 R U' B L U F' B' D U B R' B2 F R2 D2 L R2*
  • FMC272: D2 L D' L2 U R' L2 B L R2 F D2 L R B' R F' R B' U' D L2 B' R D' R2 L2 F2 U' B*
Taken from this post and this post. Cielo's scramble may be the hardest in this list.
The mark '*' at the end means that no one has achieved Sub 30 AFAIK. Be first! :)
 
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irontwig

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[*]by Cielo: L' R2 B2 D2 B2 R' B L' D' U F' L' F2 D' R2 B' U2 R F2 U'*

Sorry for being too lazy to find insertions by myself, but:
The Scramble
L' R2 B2 D2 B2 R' B L' D' U F' L' F2 D' R2 B' U2 R F2 U'
Your Skeleton
F2 R2 U2 B L2 R2 B2 U2 D2 B' F2 U' F2 B2 R L' F B2 D' U R2 U2
Result
2 edge 3-cycle(s) insertion(s) needed
F2 R2 U2 B L2 [@1] R2 B2 U2 D2 B' F2 U' F2 B2 R L' F B2 D' U R2 U2
Insert at @1: R' D2 F2 U2 L F2 D2 B2 R2
After the 1st insertion: F2 R2 U2 B L2 R' D2 F2 U2 L F2 U2 B' F2 U' F2 B2 R L' B2 [@2] F D' U R2 U2
Insert at @2: U2 F U D' L' U2 L U' D F'
Fewest moves: 29. 12 moves cancelled
The final solution: F2 R2 U2 B L2 R' D2 F2 U2 L F2 U2 B' F2 U' F2 B2 R L' B2 U2 F U D' L' U2 L R2 U2
Runtime: 9.529 milliseconds

CF heaven
 

Sebastien

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Thanks everyone! :)

After finding the 20 move skeleton after ~20 minutes I was extra careful with finding the insertions. I can't remember ever being so nervous during an FMC attempt at home as I was yesterday, especially after finding the first insertion with 5 moves cancelation! :D

Can you share your experience about finding two insertions within one hour?
I just wonder how you found the optimal insertions.

There is not so much to share actually. What I do for >= 2 insertions is, as for every kind of insertion, sticker the pieces appropriately and go through the skeleton. For the first insertions I search for bigger cancelations and I usually ignore cancelations below 3. Often there is one insertion dominating the others, so I take this as basis for my "new" skeleton and search for inserting the remaining pieces. Sometimes there are 2 good first insertions, then I just check for both resulting skeletons. I think I have never had more then 2-3 equally good first insertions.

In theory, this approach does not guarantee you the optimal insertions (even assuming you find the optimal ones in each step). So this has to be seen as heuristic. It works amazingly good though, I always check my insertions for optimality after an attempt and I think I missed optimality not more than 1 or 2 times during the last 1-2 years, and this might have rather been my fault not seeing a specific insertion.

I guess to do this regulary, you need to become fast and accurate with insertions. Inserting for skeletons were 2 insertions are needed usually takes me ~10 minutes. This naturally depends on how obvious the insertions are.

2 insertions is definitely not the limit. I've had two attempts in competition this year resulting in a 26 where 3 insertions were involved (Velbert Open 2013, 2nd attempt, BW Open 2013 2nd attempt).
 
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kinch2002

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Sébastien: For 2 insertions, I just go through once writing down all the insertions that cancel moves. Then I look for the best combo of 2 insertions that will solve everything. Have you ever tried this? I think it's quite fast and possibly covers more options than your 2-pass method does
 

Brest

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kinch: Once you've found insertion with the most moves cancelled, do you look for an insertion within that insertion?
 

okayama

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Sébastien & Daniel: I found previous posts from this thread: by Kinch and Kryptonite, may be useful for this topic (double-insertion).

I like this 1-pass approach. But as Brest pointed out, this approach misses the option: commutator into commutator.
If I have a time, of course I investigate it, and I believe Daniel does too (judging from his previous post).

For a 5-corner cycle, this approach works fine, but I wonder if there's a good way for 4 corners...
 

irontwig

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Sébastien & Daniel: I found previous posts from this thread: by Kinch and Kryptonite, may be useful for this topic (double-insertion).

I like this 1-pass approach. But as Brest pointed out, this approach misses the option: commutator into commutator.
If I have a time, of course I investigate it, and I believe Daniel does too (judging from his previous post).

For a 5-corner cycle, this approach works fine, but I wonder if there's a good way for 4 corners...

Seems a bit over-complicated, I just do the insertion that cancels the most amount of moves and leaves three corners first. And yeah, with 4 corners you have to keep track of the orientations too. Just going through the skeleton twice might be the best compromise of simplicity and speed.
 

Sebastien

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Sébastien: For 2 insertions, I just go through once writing down all the insertions that cancel moves. Then I look for the best combo of 2 insertions that will solve everything. Have you ever tried this? I think it's quite fast and possibly covers more options than your 2-pass method does

Writing down ALL insertions that cancel moves? That sounds like lots of work and most of this work will be useless.

What I like about my approach is especially is, that huge cancelations are very difficult to miss. Finding the next insertion is easier then, as you have less pieces to track and it is less likely to miss the best second insertion.

I have never tried your approach though (well, at least not exactly as you do it). How much time does this take you?
 
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