#### winniethe2

##### Member
So I was practicing a couple of FMC attempts for an upcoming competition and I got this scramble and resulting solution:

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

F' U R D2 L2//Xcross (5/5)
R U' L' U' L U2 R'//multislot (7/12)
U2 L' B L B'//last slot (5/17)
B U2 B2 R B R' U2 B' R B R' U//LL (12-2/29-2)

Thanks to some luck and multislotting, I managed to solve it in 27 moves, which is my personal best by quite a bit. I showed it to my more experienced friend who later told me than my solution would not be WCA legal since the first five moves of my solution are the inverse of the last five moves of the scramble. I honestly did not notice at all until he mentioned it since the first five moves made an Xcross and I didn’t see any other good alternatives. And yet apparently, this alone is enough to completely void my best solve to date.

Upon doing some research, I found that this rule is in effect because otherwise, people would simply reverse the scramble entirely and get a very good solve. I also learned that ‘suspicious’ solutions were subject to required explanations of the moves made, and final decisions on the solution’s legitimacy were at the delegates’ discretion. I think these rules are flawed in both the execution of FMC and the subjectivity of determining legitimacy.

#### guysensei1

##### Member
Could you explain what you mean by 'flawed'?

#### genericcuber666

##### Member
get moar people to check if its legit then fam innit

#### winniethe2

##### Member
Could you explain what you mean by 'flawed'?
Ok sure, firstly there's the issue with the treatment that ‘suspicious’ solutions get in competitions. Every part of this is handled at the whims of the delegates; whether a solution is ‘suspicious’, whether an explanation is required, whether the explanation makes sense, and ultimately whether the solution is legitimate. This is a shocking amount of subjectivity for a competitive sport. What if the delegate in question didn’t understand my algorithms or reasoning? What if I simply happened upon a shortcut to a simplified state? What if the delegate simply doesn’t like that my inferior method managed to perform better than expected? There certainly appear to be zero measures to ensure abuse of the rules from the other side doesn’t occur.

#### pglewis

##### Member
The WCA Delegate may ask the competitor to explain the purpose of each move in their solution, irrespective of scrambling algorithm. If the competitor cannot give a valid explanation, the attempt is disqualified (DNF).

Cheating is a sad reality and cheats that get into official results can damage the reputation and legitimacy of the organization. The way I'm reading the rules is it's just a way to deal with this potential problem. Yes, it's subjective but what other recourse could be considered to deal with this? Have you or anyone you know been DNF'ed over it, or is this just theoretical?

#### winniethe2

##### Member
Cheating is a sad reality and cheats that get into official results can damage the reputation and legitimacy of the organization. The way I'm reading the rules is it's just a way to deal with this potential problem. Yes, it's subjective but what other recourse could be considered to deal with this? Have you or anyone you know been DNF'ed over it, or is this just theoretical?

Since my solve was just a practice attempt, this is currently just a theoretical question. Although if this were in an actual competition, I would be required to adequately explain my moves and might potentially get a DNF.

Unfortunately, the problems I mentioned earlier exist only because reversible scrambles and as you said, cheating, exist. But I think the current rules are not an inevitable result of the circumstances of FMC.

Suppose reversing the scramble was legal and that all scrambles are shorter than 80 moves. Each person competing in FMC now have two options: reverse the scramble, or solve it normally and hope to do better than the reversed scramble. For sufficiently good competitors, it is optimal to opt for the latter since they can do better, and for the rest, reversing the scramble is optimal. Since the premise of FMC is to solve the scrambles and not reverse them, the rules must in some way make reversing the scrambles unoptimal for everyone. Currently, that is done by placing an outright ban on deriving any part of the solution from the scramble, but this can never be implemented adequately. There is no objective standard for what is and isn’t derived from the scramble. Example: If F2 is written in the scramble, then a case can be made for forbidding any F2s in a solution. This might seem pedantic, but this is a major flaw and WCA has recognised this vagueness of the rules. As such, they consider every solution that has undone 4 or 5 or more moves as ‘suspicious’ and have delegates check every solution that appears ‘suspicious’. As mentioned before, however, this is incredibly subjective and arbitrary. And not surprisingly. The lack of an objective standard in defining what is and is not derived from the scramble will cause issues no matter how you slice it. As such, another method must be found to make reversing scrambles universally unoptimal.

The straightforward idea is to make the scrambles longer, such that reversing them yields a relatively poor solution. The problem with this is that there are thousands of cubers, with wildly varying strengths and ability. There will always exist people for whom reversing the scramble is more optimal than attempting to solve the scramble manually, especially if they can’t even make the 80-move cutoff otherwise. All this leads to the obvious solution: make the scrambles longer than 80 moves. In fact, just 81 moves are sufficient. An 81-move scramble ensures that reversing the scramble is universally unoptimal because it universally results in a DNF. Even writing 80 random moves provides a greater chance of getting a working solution. This is also easily generated by stringing three or four normal scrambles together, ensuring that the randomness is maintained throughout the scramble. I think doing this will make FMC fairer and cleaner.

#### Mollerz

##### Swag Overlord
The scramble is buffered on either end by R' U' F <scramble> F' U R. So this is purely luck that the final three moves of the scramble are the same as the start of the solution. So this would be fine. Any delegate that disallowed it doesn't understand the TNoodle buffering for FMC.

#### Jaysammey777

##### Member
But this would affect the time it takes to scramble. And In fmc you can scramble the cube up to 100 times in some cases.

#### pglewis

##### Member
I personally think the fairest way to evaluate situations like this is case by case, from the competitors' standpoint... which means a subjective ruling vs. hard and fast objective means. You explained how you derived your solution, count it .

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#### guysensei1

##### Member
Have you or anyone you know been DNF'ed over it, or is this just theoretical?
This guy though admittedly it was before the R' U' F era

The scramble is buffered on either end by R' U' F <scramble> F' U R. So this is purely luck that the final three moves of the scramble are the same as the start of the solution. So this would be fine. Any delegate that disallowed it doesn't understand the TNoodle buffering for FMC.
Yes but this exactly what OP is talking about, the decision to legitimize a solve is entirely at the delegate's discretion and this is subjective.

Btw is there anywhere I can read up on why/how R' U' F was chosen?

#### Jaysammey777

##### Member
This guy though admittedly it was before the R' U' F era

Yes but this exactly what OP is talking about, the decision to legitimize a solve is entirely at the delegate's discretion and this is subjective.

Btw is there anywhere I can read up on why/how R' U' F was chosen?
It switches edge orientation, meaning these moves are unlikely to happen with the way they affect eo

Edit: search the wca regulations GitHub, I think it's in there.

#### Mollerz

##### Swag Overlord
Yes but this exactly what OP is talking about, the decision to legitimize a solve is entirely at the delegate's discretion and this is subjective.

Btw is there anywhere I can read up on why/how R' U' F was chosen?

I can't tell you why R' U' F was chosen, it's quite easy to execute so that probably helped. We just needed some extra moves.

But what I'm saying is that this solution should not be disallowed because of the way the buffering works. And if a delegate does then they are not performing their duties as a delegate correctly. We see in reports when FMC solutions have been disallowed due to inverse scramble similarity. And so far every time since the addition of this buffering, it has been because the whole scramble has been reversed.

#### One Wheel

##### Member
Is it even remotely feasible to change the format of FMC entirely, so that instead of receiving a scramble competitors instead submit up to 3 cubes, which are then scrambled by someone else and returned to start the attempt? This would be more work for the organizing team, obviously, but would completely eliminate the issue of reversing the scramble (unless somebody got ahold of it when they shouldn't, but that could be an issue for any event). If somebody wants to solve in a different orientation than white top, green front they would need to write cube rotations into their solution, but that's not really a problem as I see it.

#### bubbagrub

##### Member
Is it even remotely feasible to change the format of FMC entirely, so that instead of receiving a scramble competitors instead submit up to 3 cubes, which are then scrambled by someone else and returned to start the attempt? This would be more work for the organizing team, obviously, but would completely eliminate the issue of reversing the scramble (unless somebody got ahold of it when they shouldn't, but that could be an issue for any event). If somebody wants to solve in a different orientation than white top, green front they would need to write cube rotations into their solution, but that's not really a problem as I see it.

That would be a totally different event. No insertions, no premoves, no NISS, just linear solves. Much less interesting, I'd say...

I also hope we don't adopt the suggestion above of 80 move scrambles... That would make the event a real pain...

#### One Wheel

##### Member
That would be a totally different event. No insertions, no premoves, no NISS, just linear solves. Much less interesting, I'd say...

I also hope we don't adopt the suggestion above of 80 move scrambles... That would make the event a real pain...

I guess what little FMC I've done is basically linear solving, and I've enjoyed it. Somehow though I'd thought the point of insertions was after you have a skeleton, say F2l solved, you go back and modify that F2l to get a LL or partial LL skip?

#### Cale S

##### Member
That would be a totally different event. No insertions, no premoves, no NISS, just linear solves. Much less interesting, I'd say...

I also hope we don't adopt the suggestion above of 80 move scrambles... That would make the event a real pain...

You can use all those techniques if you are given only a scrambled cube

Just write down a linear solution and invert it to get a (rather long) scramble sequence

I think the way we have now with modified scrambles is good enough

#### EmperorZant

##### Member
What if the delegate in question didn’t understand my algorithms or reasoning? What if I simply happened upon a shortcut to a simplified state? What if the delegate simply doesn’t like that my inferior method managed to perform better than expected?
I think a core component to FMC is that you're supposed to find a unique solution. One can argue that their solution is identical (at least in part) to the scramble because "that's how I'd solve it." And that's perfectly understandable, and very well could be the truth, but no one can prove it; which is why we need some sort of safeguard (in this case, delegates' discretion). That's just how I think about it.
Also, the suggestion to make 80-move scrambles for 3x3 sounds a little ridiculous. I do like the idea of increasing it to maybe 30 or 40, but quadrupling the amount of time it takes to scramble the cube in an event where time is so crucial might be too extreme of an approach. Gotta' keep it practical!

#### mDiPalma

##### Member
I know this is going to sound stupid, but I always found the fact that FMC competitors are given a written scramble AT ALL to be somewhat impure.

Why not just give them a single scrambled cube, as in all the other events?

Make them match-the-scramble to find a "scramble" for the cube. Then they can use that as their "scramble" and even do NISS, etc.

I understand that would drastically (negatively) affect the way FMCers find solutions and waste a minute or two (from the arbitrary 1-hour limit), but it would certainly avoid this entire debate and would standardize the regulations.

#### winniethe2

##### Member
I think a core component to FMC is that you're supposed to find a unique solution. One can argue that their solution is identical (at least in part) to the scramble because "that's how I'd solve it." And that's perfectly understandable, and very well could be the truth, but no one can prove it; which is why we need some sort of safeguard (in this case, delegates' discretion). That's just how I think about it.
Also, the suggestion to make 80-move scrambles for 3x3 sounds a little ridiculous. I do like the idea of increasing it to maybe 30 or 40, but quadrupling the amount of time it takes to scramble the cube in an event where time is so crucial might be too extreme of an approach. Gotta' keep it practical!
As mentioned by Cale S, providing cubes pre-scrambled actually solves a lot of issues. Simply writing down a linear solution once, then inverting it immediately yields a much shorter ‘scramble’ than 81 moves. Using Petrus or ZZ, the ‘scramble’ will be around 40 moves long which is kind of the ideal place for it to land, not too long to make repeated scrambling tedious. So making the initial scramble 81 moves long doesn’t actually mean you have to spend a ridiculous amount of time setting up the scrambles, but ensures that there’s a backup plan if you screw up all three pre-scrambled cubes and still completely disincentivises reversing the initial scramble to get a solution.

#### Robert-Y

##### Member
What about using a small combo of <S2,E2,M2>? To me, it doesn't seem likely to begin a solution with a combo of such moves...