# What does the regulation 4b3a (about scramble filtering for blindfolded events) mean?



## Gorisanson (Mar 5, 2015)

I don't understand what the following regulation mean..


> 4b3a) For blindfolded events, the scramble sequence must orient the puzzle randomly (equal probability for each orientation).
> (https://www.worldcubeassociation.org/regulations/#4b3a)



What does this mean? What scrambles are filtered by this regulation? Give me some examples, please..


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## biscuit (Mar 5, 2015)

In bld scrambles orientation is part of the scramble... I believe. Marcin was banned because he knew the orientation of the cube before the solve. So the orientation was NOT random


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## Ollie (Mar 5, 2015)

Example scrambles:

R U R' U' Rw Uw
B L D B Lw' Dw



Spoiler



The orientation of centers changes. No scrambles are filtered out, just adjusted to randomize orientation further before it is placed in the box and taken to the solving station


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## Gorisanson (Mar 5, 2015)

Ollie said:


> Example scrambles:
> 
> R U R' U' Rw Uw
> B L D B Lw' Dw
> ...



Oh, Thanks a lot! I got it!

But.. by the following regulations, the judge places the cube onto the mat in arbitrary position on blindfolded events. So I think the regulation 4b3a is meaningless, isn't it...?



> B1) Standard speed solving procedures are followed, as described in Article A (Speed Solving). Additional regulations that supersede the corresponding procedures in Article A are described below.
> B1a) There is no inspection period.
> B1b) The competitor supplies his own blindfold.
> (https://www.worldcubeassociation.org/regulations/#B1)
> ...


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## Goosly (Mar 5, 2015)

Gorisanson said:


> But.. by the following regulations, the judge places the cube onto the mat in arbitrary position on blindfolded events. So I think the regulation 4b3a is meaningless, isn't it...?



Judges will almost never take the cube and toss it in the air to get a random orientation. The scramble ensures there is a random orientation, followed by whatever the judges does. The orientation will therefor always be random.


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## Gorisanson (Mar 5, 2015)

Goosly said:


> Judges will almost never take the cube and toss it in the air to get a random orientation. The scramble ensures there is a random orientation, followed by whatever the judges does. The orientation will therefor always be random.



Oh, Thank you! I perfectly understand now.
Thank all of you!


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## Lucas Garron (Mar 5, 2015)

Goosly said:


> Judges will almost never take the cube and toss it in the air to get a random orientation. The scramble ensures there is a random orientation, followed by whatever the judges does. The orientation will therefor always be random.



Yep, this is pretty much right.
There was no requirement to randomize the orientation – scramblers/judges weren't required to do anything to the orientation after applying the scramble, and the competitor received an "arbitrary" orientation.

The issue was that *some* people ended up with consistent orientations while *some* people didn't. We wanted to make it clear that no competitor should get an advantage about knowing the orientation of the cube.

Giving everyone a consistent orientation (e.g. white center on top, green center in front) is probably not going to work: there will always be mistakes, and it would give competitors an unnecessary excuse to ask for an extra solve.
So the safest thing is to give everyone a random orientation. As Ollie points out, this is implemented in TNoodle using wide turns. 4b3a makes this an official requirement. 4b4+ makes it practical:



> 4b4+) ADDITION It is permitted for the puzzle to change its orientation when it is moved from the scrambler to the solving station, as long as no one is attempting to influence the randomness of the orientation (see Regulation A2e1).


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## Gorisanson (Mar 6, 2015)

Lucas Garron said:


> So the safest thing is to give everyone a random orientation. As Ollie points out, this is implemented in TNoodle using wide turns. 4b3a makes this an official requirement. 4b4+ makes it practical:



I didn't know there was an additional guideline 4b4+. Now I see what the regulations mean more clearly. Thank you!


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