[Help Thread] FMC Discussion

[okayama]

Is there any good finish from this F2L-1?
LL is always hard on FMC...

Scramble: B D R2 B2 R F2 D R2 L' F U2 R B2 U2 L' B2 L2 F2 L2

- Normal
Premove: U2 R'
2x2x3: D2 B' L U' L2
- Inverse
F2L-1: D' R D2 R' D2

My 5 min attempt.

(Inverse)
Pre-scramble: L2 U L' B D2

2x2x3 block: R U2 (your start)
Orient edges: B F' R F
More square: R B'
All but 3 corners: R2 D2 B' D2 B D' R'
Correction: L2 U L' B D2
Corner 3-cycle: D B' D' F D B D' F'

27 moves in total.

 

[Username]

How do you choose a good pre-move, and how do you know when you should do the inverse scramble?

 

[arvind1999]

okayama why didn't you change your sign yet?

 

[Cubenovice]

About FMC440

Scramble: B L2 U B2 F' R2 L F B' D' B F2 R' B U D' L2 B' L F2 B' D B2 L' R' F R' L2 D2 U'

I found the following short F2L with NISS:

F2L: D' F' L U D F2 D' F U2 B U2 B D'

but I didn't come up with any good LL/insertion. Anyone?

Did you try
F2L: D' F' L U D F2 D' F U2 B U2 B D'
L - leaves 3 corners and a H-perm

Insertion finders gives 27 HTM for this...

 

[okayama]

About FMC440

Scramble: B L2 U B2 F' R2 L F B' D' B F2 R' B U D' L2 B' L F2 B' D B2 L' R' F R' L2 D2 U'

I found the following short F2L with NISS:

F2L: D' F' L U D F2 D' F U2 B U2 B D'

but I didn't come up with any good LL/insertion. Anyone?

Did you try
F2L: D' F' L U D F2 D' F U2 B U2 B D'
L - leaves 3 corners and a Z-perm

Insertion finders gives 27 HTM for this...

I also noticed that. I firstly tried COLL+EPLL approach,
which are a Corner 3-cycle and Z-perm in this case.

But I didn't try those insertions, because I thought that
it didn't give such a short solution. Thanks for sharing.
(NB: I already got two 27-move solutions)

okayama why didn't you change your sign yet?

I believe I still cannot improve my signature.
See also my post.

 

[mycube]

hey guys, have you ever seen an optimal insertion for corners with 9 moves? here it is:

L2 F2 U2 B2 U L2 D U2 B2 U' L2 B' R' U' L2 D L' F2 L B L
L' B' L' F2 L D' L2 U R B L2 U B2 U2 D' L2 U' B2 U2 F2 L2

inv:
F‘ L‘ B2 U‘ R‘ B2 D‘ B U2 - 2x2x3 [9/9]
F‘ D2 F - F2L-1 + Pair [3/12]
L‘ F L‘ F‘ L2 D - F2L [6/18]

I was happy to find a sub20 3cycle, what you don't find that often. But on the first try I wasn't able to find even a insertion without cancellation. So I tried to do it with two insertions. But even with a first insertion with 5 move cancellation the secound one was again with just one or two moves. So I used a MGLS to finish the solution in time:
R2 U2 R D2 R‘ U2 R D2 R - 3cycle (MGLS) [9/27]

IF can't find a solution. So I did no bad work. Can anyone try to find a better solution with two insertions? I can't believe that this is the best solution for this skeleton

inverse Solution:
F‘ L‘ B2 U‘ R‘ B2 D‘ B U2 F‘ D2 F L‘ F L‘ F‘ L2 D R2 U2 R D2 R‘ U2 R D2 R

Solution:
R‘ D2 R‘ U2 R D2 R‘ U2 R2 D‘ L2 F L F‘ L F‘ D2 F U2 B‘ D B2 R U B2 L F

 

[okayama]

hey guys, have you ever seen an optimal insertion for corners with 9 moves? here it is:

L2 F2 U2 B2 U L2 D U2 B2 U' L2 B' R' U' L2 D L' F2 L B L
L' B' L' F2 L D' L2 U R B L2 U B2 U2 D' L2 U' B2 U2 F2 L2

inv:
F‘ L‘ B2 U‘ R‘ B2 D‘ B U2 - 2x2x3 [9/9]
F‘ D2 F - F2L-1 + Pair [3/12]
L‘ F L‘ F‘ L2 D - F2L [6/18]

I was happy to find a sub20 3cycle, what you don't find that often. But on the first try I wasn't able to find even a insertion without cancellation. So I tried to do it with two insertions. But even with a first insertion with 5 move cancellation the secound one was again with just one or two moves. So I used a MGLS to finish the solution in time:
R2 U2 R D2 R‘ U2 R D2 R - 3cycle (MGLS) [9/27]

IF can't find a solution. So I did no bad work. Can anyone try to find a better solution with two insertions? I can't believe that this is the best solution for this skeleton

inverse Solution:
F‘ L‘ B2 U‘ R‘ B2 D‘ B U2 F‘ D2 F L‘ F L‘ F‘ L2 D R2 U2 R D2 R‘ U2 R D2 R

Solution:
R‘ D2 R‘ U2 R D2 R‘ U2 R2 D‘ L2 F L F‘ L F‘ D2 F U2 B‘ D B2 R U B2 L F

Here is a better solution based on your nice skeleton.

All but 3 corners: D' L2 F L F' L F' D2 F * U2 B' D B2 R U B2 L F
A-perm: F (U' F D2 F' U F D2 F') F'

or Insert at *: F (L2 F R2 F' L2 F R2 F') F'

FYI: The same happened several times (e.g. here and here)
My previous skeleton (link) is quite rare, truely 9-move is needed for a single insertion.

EDIT: (sorry, I didn't try two insertions)

 

[Sebastien]

Hi Tomoaki,

I found these insertions too (and so won a beer from Linus! ). Furthermore I tried 2 insertions with very desperate results. I found ~20 first insertions with >= 4 move cancelation, put the skeletons in the IF each time and never got below 28 moves (or 2 moves cancelation respectively).

Actually I learned a lot by working with that scramble. It was weird trying to solve 3 corners with 2 insertions, hence turning this very linear problem to a rather non-deterministic problem. Furthermore I still can't believe, that none of my first insertion tries gave me a better result as the direct insertion. But thinking more about it it makes sense, that the relative position of the corners to each other doesn't improve so much by switching the skeletons in this way.

anyway, I'd be happy to try this again on a scramble where a normal insertion provides terrible results only. the gain might be better on a scramble, where you land in lots of 8 move positions but none with a cancelation.

 

[mehdi-roshan]

hi

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

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


2X2X3 Block : L' B' [@] L R2 U L R' U L2 //(9/9)
All but 5 corners : F' D' F' D [#] F D F2 D2 F (9/18)
Insert at @ = B' R B L B' R' B L' //(8-3/23)
Insert at # = U' B2 U F2 U' B2 U F2 //(8-1/30)

Final solution :L' B2 R B L B' R' B R2 U L R' U L2 F' D' F' D U' B2 U F2 U' B2 U F' D F2 D2 F (30 HTM)

 

[okayama]

My winning solution in Kansai Open 2013.

Scramble: D' U' L2 B2 L2 F2 D' L' R' B L' U2 L2 D R B2 F' D2 U2
Solution: F U2 F' D' F U2 F' R' B' D B2 D2 U2 L' F2 L' F2 L F2 L' F' D' L D L F2 U R D' (29 moves)

Spoiler

30 min backup solution.

Pre-scramble: D' L D L F2 U R D'

1st square: (ready)
2nd square: D' R' B'
3rd square: D B2 D2 U2
F2L minus 1 slot: L2
All but 3 corners: L F2 L' F2 L F2 L' F'
Correction: D' L D L F2 U R D'

Insert at the beginning: F U2 F' D' F U2 F' D

Seems a nice scramble, but I couldn't find any better solution in time.

Hideki Niina (2nd place) showed me his quite a short start for F2L minus 1 slot,
so if you're interested go ahead to continue:

Spoiler

1st square: U2 F2 U
c/e pair: L'
2x2x3 block: R' B R2
F2L minus 1 slot: L D2 L

 

[elrog]

Could anyone tell me what exactly the point of premoves is? Why do some moves before you scramble just to undo them afterwards?

 

[Attila]

My have a question.
I found a 24-move solution for Kansai Open scramble:

Spoiler

Scramble: D' U' L2 B2 L2 F2 D' L' R' B L' U2 L2 D R B2 F' D2 U2
Solution: U2 D2 F2 D L2 U R' U2 R B L R' U' B2 L2 R2 F' R L' U' L R2 D2 R
Explanation:
U2 D2 2nd c-e pair,
F2 D L2 U orient corners and 4 edges,
R' U2 R all corners - 2 moves,
B L R' U' more 2 edges,
B2 L2 R2 F' R L' U' L R2 D2 R L6E.
Lucky solution for me, i found in 25 mins.

Although this was not my intention, the first 3 moves of solution,
and the last moves of scramble similar.
This solution is acceptable or not?

 

[Noahaha]

My have a question.
I found a 24-move solution for Kansai Open scramble:

Spoiler

Scramble: D' U' L2 B2 L2 F2 D' L' R' B L' U2 L2 D R B2 F' D2 U2
Solution: U2 D2 F2 D L2 U R' U2 R B L R' U' B2 L2 R2 F' R L' U' L R2 D2 R
Explanation:
U2 D2 2nd c-e pair,
F2 D L2 U orient corners and 4 edges,
R' U2 R all corners - 2 moves,
B L R' U' more 2 edges,
B2 L2 R2 F' R L' U' L R2 D2 R L6E.
Lucky solution for me, i found in 25 mins.

Although this was not my intention, the first 3 moves of solution,
and the last moves of scramble similar.
This solution is acceptable or not?

Of course, as long as you can explain why you made those moves.

 

[Cubenovice]

Could anyone tell me what exactly the point of premoves is? Why do some moves before you scramble just to undo them afterwards?

http://www.speedsolving.com/forum/showthread.php?13599-The-FMC-thread&p=784498&viewfull=1#post784498

 

[elrog]

That gives me the impression that you get to see the scramble before you choose a premove? Heck the FMC rules really are screwy.

EDIT: In my opinion, you shouldn't be allowed to see the scramble, or/and the scramble should be excessively long to keep people from using its inverse or being accused of it when they were not trying to.

 

[mehdi-roshan]

Scramble: R2 D U2 B2 F' U2 R' L2 B' U D2 L2 R2 D2 B2 U2 D' L R' U' L' B' F' L' R' U' B F2 L' B2

1X2X3 block : L2 F D'B' D F' U2 R' //(8/8)
F2L minus 1 slot : U B L [#] B' L' B U //(7/15)
All but 3 corners : D2 L D L' F' D' F D' F' D' F //(11/26)
Insert at # = L' F L B' L' F' L B //(8-6/28) ===> cancelling 6 move !!!!!!!

Final solution: L2 F D'B' D F' U2 R' U B F L B' L' F' B U D2 L D L' F' D' F D' F' D' F (28 HTM)

 

[okayama]

Scramble: R2 D U2 B2 F' U2 R' L2 B' U D2 L2 R2 D2 B2 U2 D' L R' U' L' B' F' L' R' U' B F2 L' B2

1X2X3 block : L2 F D'B' D F' U2 R' //(8/8)
F2L minus 1 slot : U B L [#] B' L' B U //(7/15)
All but 3 corners : D2 L D L' F' D' F D' F' D' F //(11/26)
Insert at # = L' F L B' L' F' L B //(8-6/28) ===> cancelling 6 move !!!!!!!

Final solution: L2 F D'B' D F' U2 R' U B F L B' L' F' B U D2 L D L' F' D' F D' F' D' F (28 HTM)

Nice to see your recent attempts in fmc.mustcube.net.
Do you know there is a weekly competition in this forum? (cf. this week)
Try it if you're interested.

I noticed that your solution above was posted for FMC442/speed,
but you are not allowed to search an insertion. See FMC rules for `Speed challenge'.
There are several important rules for speed that are quite different from 1-hour/classic.

 

[Cubenovice]

That gives me the impression that you get to see the scramble before you choose a premove? Heck the FMC rules really are screwy.

EDIT: In my opinion, you shouldn't be allowed to see the scramble, or/and the scramble should be excessively long to keep people from using its inverse or being accused of it when they were not trying to.

In a competition you get the scramble and then can use up to three cubes (and stickers) to find the shortest solution withing one hour.
Scramble length is really not an issue.
If you have some starting moves in common with the inverse scramble you typically have a good reason for it: for instance to make a pair or a square.
If you would check the inverse scramble further you will find that this pair or square is never intact through the full scramble.

 

[elrog]

Having a long scramble or not seeing the scramble is still needed to prevent people from using it. Using the NISS method isn't really solving the cube in as few moves as possible by human intellect.

 

[The Supreme One]

IIRC, they are actually given a cube, and are told exactly what the scramble was