[Help Thread] FMC Discussion

[okayama]

Hi

After all the easy scrambles, here is a really hard one!
It was the scramble of the Dutch Open 2009 FMC competition october 17 2009:

R2 D B2 U B2 D B' D' R' U' F' D2 B2 R D L' B' F (18)

Winning solution was 35 moves bij Erik and me
(posting solution on request)

Gus

I found this post, and tried.

Solution: F' U2 L U L' U B2 D' R D B2 F D' B U2 F' L2 F2 U' R U R' B R' B' R F' R D' L2 (30 HTM)

(For inverse scramble)

Pre-scramble: U2 B' D

1st 2x2x1 block: L2 D R'
2nd 2x2x1 block: F R' B R
3rd 2x2x1 block: B' R U' R'
F2L minus 1 slot: U F'
All but 2 edges/2 corners: F' L2 F
Correction: U2 B' D
Setup+J-perm: F' (B2 D' R' D B2 U' L U' L' U2) F

There might be another good insertion, but I ran out of time...

 

[okayama]

Correct explanation for FMC #310 classic

Scramble: 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)

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

1) and 2) are based on a simplified Thistlethwaite approach.
(Hard scramble for my usual approach)

 

[satya]

@okayama: please suggest a nice insertion for the same scramble(FMC-310)
with premoves:RUR'
L F2 L' F' B2 R2 L'F' R F' R 'F2 R F2 D F' D'(17 moves) leaves 5 edges.
how will you end this?

 

[okayama]

@okayama: please suggest a nice insertion for the same scramble(FMC-310)
with premoves:RUR'
L F2 L' F' B2 R2 L'F' R F' R 'F2 R F2 D F' D'(17 moves) leaves 5 edges.
how will you end this?

Your skeleton: L F2 L' * F' + B2 R2 L' F' R F' R' F2 R F2 D F' D' R U R' (20 HTM)

Insert at *: L S2 L' F' L S2 L' F
Insert at +: L2 U' L2 f2 L2 U' L2 f2 (or L2 U' L2 B2 R2 D' R2 B2)

Final solution: L f2 L' F' L S2 L U' L2 B2 R2 D' L' F' R F' R' F2 R F2 D F' D' R U R' (27 HTM)

I stopped searching insertions at +, so they might not be optimal. Keep trying by yourself!

 

[guusrs]

Correct explanation for FMC #310 classic

Scramble: 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)

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

1) and 2) are based on a simplified Thistlethwaite approach.
(Hard scramble for my usual approach)

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

 

[okayama]

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

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...

 

[kinch2002]

FMC at Swedish Open 2010
Scramble: R2 B2 R B2 R' B2 R' F2 D2 U2 F2 R' F' L' B2 U L2 D B' L2 R2 (21f)
Solution: U F' L F2 U2 R2 U R' B' L2 D L D B D B' D2 B D B' R' B R2 U2 R' D R U2 R' (29 moves NR)

2x2x3: U F' L F2 U2 R2 U R' B' L' (10) The B' is to preserve a pair
Switch to inverse scramble with premoves L B R U' R2 U2 F2 L' F U'
F2L-1: D' R' B' R (14) The D' is to orient 2 edges
Switch back to normal scramble with premoves R' B R D, then apply the 2x2x3 block moves
Make LL block and finish F2L: L' D L D B D B' D2 B D B' (24) Leaves 3 corners
That creates the insertion-less solution as U F' L F2 U2 R2 U R' B' L2 D L D B D B' D2 B D B' R' B R * D
At *, insert R U2 R' D R U2 R' D' to cancel 3 moves, giving 24+8-3=29 moves

 

[palash_du]

Hi,
I tried FMC for this weeks competition at mustcube! This is my first solve and as a result it is very bad. Please have a look and see if there is something you can insert.

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

Solve:
2x2x3 block: L' U' R D R D2 U2 B
Orienting & permuting corners: B U' B'U' R2
R' F' L' F R F' L F
F' L F' R2 F L' F' R2 F2
now a 5 cycle of edges remains
FB'R'F'B
RF2U'R'LF2L'RU'F2
R'U

The whole solution is: L' U' R D R D2 U2 B2 U' B'U' R F' L' F R F' L2 R2 F L' F' R2 F' B' R' F' B R F2 U' R' L F2 L' R U' F2 R' U

The whole solution is 40 moves. Nice for a start!!

 

[irontwig]

Hi,
I tried FMC for this weeks competition at mustcube! This is my first solve and as a result it is very bad. Please have a look and see if there is something you can insert.

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

Solve:
2x2x3 block: L' U' R D R D2 U2 B
Orienting & permuting corners: B U' B'U' R2
R' F' L' F R F' L F
F' L F' R2 F L' F' R2 F2
now a 5 cycle of edges remains
FB'R'F'B
RF2U'R'LF2L'RU'F2
R'U

The whole solution is: L' U' R D R D2 U2 B2 U' B'U' R F' L' F R F' L2 R2 F L' F' R2 F' B' R' F' B R F2 U' R' L F2 L' R U' F2 R' U

The whole solution is 40 moves. Nice for a start!!

Just doing last three corners at the end I found this 35 mover with your 2x2x3:

L' U' R D R D2 U2 B R U' R U' R' F' U2 F U2 B U' B' U' R' U' R U' R' U R2 D R' U' R D' R' U'

L' U' R D R D2 U2 B [2x2x3]
R U' R U' R' F' U2 F [EO]
U2 B U' B' U' R' U' R U' R' U R . U2[Leaving 3 corners]
Insert at dot: R D R' U' R D' R' U (Cancels two moves)

Very nice beginning, especially for a first-timer!

 

[zaub3rfr4g]

Need help for two solves

#1
scramble: L F2 B D2 F' L U' B2 R2 U' R D2 R2 L' U F' B2 D2 U' D F2 U2 L' B L

x y2 F L' U B' R2 D' F' 2x2x3 - 1 edge
U' L B' L' B U R' triple x cross (14)
and now...?

#2
scramble: R2 F B L' D2 U F2 U' L R' D' L2 U2 B' R D2 U' L2 R2 F D2 B' L2 B U

L' D' 2x2x2
U' create a pair
R' U' B R2 U' B U2 B triple x cross (11)

now i can't find a decent ending

 

[irontwig]

1#: Rotations? Yuck.

2#: Leaves three corners: F R' F' R2 B U B' U R' U' R U R' (24) (Premovish strategy with R') Too lazy to search for an insertion. But if you bother to look for one, it can be sub-30 if you find a place to cancel 3 moves.

 

[Johannes91]

My solution from Swedish Open 2010:

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

S1+2: U2 F U D' L F2 B L2
S3+4a: F' B R' B' R F
S4b: D2 L' D' L D' R' B2 R
ZBLL: R' B' R2 B R2 B R2 B2 R2 B2 R B (31f)

I really don't like the end, but couldn't find anything better.

 

[palash_du]

Hi,
I tried FMC for this weeks competition at mustcube! This is my first solve and as a result it is very bad. Please have a look and see if there is something you can insert.

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

Solve:
2x2x3 block: L' U' R D R D2 U2 B
Orienting & permuting corners: B U' B'U' R2
R' F' L' F R F' L F
F' L F' R2 F L' F' R2 F2
now a 5 cycle of edges remains
FB'R'F'B
RF2U'R'LF2L'RU'F2
R'U

The whole solution is: L' U' R D R D2 U2 B2 U' B'U' R F' L' F R F' L2 R2 F L' F' R2 F' B' R' F' B R F2 U' R' L F2 L' R U' F2 R' U

The whole solution is 40 moves. Nice for a start!!

Just doing last three corners at the end I found this 35 mover with your 2x2x3:

L' U' R D R D2 U2 B R U' R U' R' F' U2 F U2 B U' B' U' R' U' R U' R' U R2 D R' U' R D' R' U'

L' U' R D R D2 U2 B [2x2x3]
R U' R U' R' F' U2 F [EO]
U2 B U' B' U' R' U' R U' R' U R . U2[Leaving 3 corners]
Insert at dot: R D R' U' R D' R' U (Cancels two moves)

Very nice beginning, especially for a first-timer!

Thanks!

Nice to see a 35 mover of my solve !!!
Can you explain how you figure out insertions in a particular solve. I do not seem to get the hang of that!

 

[irontwig]

Heise has a page on how to recognize and solve 8-move cases:

http://www.ryanheise.com/cube/corner_3_cycles.html

What you can do is stickering the pieces you need to cycle according to their sticker cycle ("This sticker ends up here and this one here"). When I try insertions I sticker one cycle like 1->2->3 and the other one A->B->C so each corner has two stickers. Then you just step through the solution and take note of every time you see that the corners has solvable with a 8 mover. For the solution above I didn't need any stickers, since I did the insertion at the end where it's obvious where every corner needs to go.

hth

 

[Kenneth]

Weekly (D' F D' F' L' D L2 R U2 F' U' B U2 F R D F2 U'), I had a 12 move triple x :

U' D' L2 D' B2 U D2 L' D F2 D2 L'

But the rest sucked so I took a DNF.

Edit, Hmm, just found this for last pair and EO : F' D2 F *

* alt 1 : D2 F L' F' L D L B' L' B
* alt 2 : D' L B' L' B D' F L' F' L

Both gives 25 and the same ZBLL case, that I don't know, both my COLL and it's mirror leaves a U-PLL

 

[irontwig]

Kenneth,I found 30 move solution with your first 10 moves (gotta take care of those bad edges!):

U' D' L2 D'.B2 U D2 L' D F2
D' B D' B2 L' B
L' D L D' L' D' L D2

Insert at dot: D R' D' L' D R D' L (Two moves cancel)

Stealing others' beginnings is pretty fun.

 

[Kenneth]

Yes, the edges sucked, that's why I did not find a good end. I must work on a few standard ways to avoid situations like that.

Nice work Mr Stålgren =)

You should have come to SOC, you are a potentional winner in FMC. (Next time will probably be the Cube day in "Blackan", be there!)

 

[hiep_h1tv]

first
i'm just a newbie and i'm vietnamese so my english not well
so some words i said is wrong,srr
second
i just start FMC for a week.
i finish the cube by xcross>f2l>zbll but some zbll i don't know
i need someone help me about that
thank all

 

[Stini]

Here's my yet another sub-30 solve from Estonian Open:

Scramble: D2 L2 F D2 U2 B R2 U2 F' U2 R' D R U2 L' U' R2 F' L2 U F
(Inverse scramble: F' U' L2 F R2 U L U2 R' D' R U2 F U2 R2 B' U2 D2 F' L2 D2)

Solution: F' B2 R2 B U R U' R2 B2 R' B2 R2 B R' D' L2 D R D' L2 R' U' R2 B2 L' (25 HTM)

Pre-move for the inverse scramble: F

2x2x3: L B2 R2 U R D.
Pseudo F2L minus slot: B' R2 B2 R B2
Leave 3 corners: R2 U R' U' B' R2 B2

Insert D' L2 D R' D' L2 D R at the dot to cancel 2 moves.

I didn't have much time in the end so I was rushing a bit and I felt quite nervous so it's possible that I overlooked a better insertion. I spent quite a lot of time for the start, which caused the time trouble. I was quite surprised to find such a nice start on a scramble with no pairs.

My next try will be in the European championships, I feel anxious already.

 

[irontwig]

Isn't that pre-move "related to the scramble" though? Not that I personally think that your solution should have been disqualified, but that's still pretty much what the regulations state.