EO Awareness during F2L (Or: How to avoid rotations)
Hello you cubers out there.
My name is Erik not Akkersdijk, living in Germany and 18 years old. I've never written an article about anything, so please don't yell at me. This is meant to be read by cubers who are still having trouble with bad F2L solving. Experienced cubers will hardly find anything new, but you may want to take a quick look if you missed something on your way.
I don't know how useful this will be. If I get positive reactions I will consider writing about other topics, too. If not, then at least I have collected some thoughts for myself.
I want to introduce you to Edge Orientation (EO) during F2L. Ever asked for advice on your video performance? A common reaction is "You make too many rotations". So there you are. But how exactly do you avoid them? In this little essay I want to explain some things you can do about rotations.
The first paragraph is about avoiding rotations without using edge control. It is simply about finding out which cases can be solved without F/B or y/y' in general. It also explains what good and bad edges are and how you recognize them, you will need that for the other paragraphs. Don't be afraid of learning about edge control and good/bad edges, it is not difficult. I promise.
1. Avoiding rotations by using R,U,L,D moves only
A good question is: What causes rotations? Roations are made to avoid awkward F and B moves. That means, every time a cuber feels the need of using F or B moves, he makes one or more roations to avoid them. A good first step is being aware of which cases can be solved rotationless with neither F nor B moves. So you can figure out the RULD solution for these cases and never make a rotation for those again.
So: Which cases can be solved with RULD only?
Here is a definition: A F2L case can be solved with RULD moves, if the edge of the pair is oriented correctly. If an edge is oriented correctly let's call it "Good edge", otherwise we call it "Bad edge". So we better use the following rule of thumb:
A F2L cases can be solved with RULD moves, if the edge of the pair is good.
It is a piece of cake to recognize if an edge is good or bad. Put the edge anywhere except the M-slice. If the R/L Sticker matches with the centerpiece or the opposite centerpiece the edge is good. If not, it's bad. You will be able to tell immediately if any edge is good once you are used to it.
Note: When you do y or y' the orientation of all edges in the U-Layer change, but the orientation of the edges in the E-Layer keep the same. A y2 changes nothing.
What you should do now is to figure out on which RULD cases you are still doing y-moves. These rotations are 100% unnecessary. Figure out the RULD solution for these cases to avoid a huge amount of y-moves during your solves. You can look up good algs on speedsolving wiki if you want to.
This is the easiest thing you can do to avoid roations. Everytime you notice you did a y-move on a good-edge-pair, find out the RULD solution for the next time.
2. Choose wisely when you use y and y' - Choose which pair you better solve next
This is a simple idea explained quickly. Imagine you have two good and two bad edges after the cross. What you want to do is to make first both good edges, then use y/y' only once to turn the other edges into good ones and solve them. Otherwise you are going to use y more than one time, which costs you time. Keep in mind that y/y' does not change an EO of the edge is in the E-slice. For example you can wait with good E-slice edges till the end. And if a bad edge is in the E-slice, you should put the edge out before you use y/y' otherwise you are going to do two rotations. Play around with it and you will get better with time.
You should tend to use y in a way that the solved slots are on the Back side for better look ahead.
3. Avoiding rotations by using sledgehammers
You need this little information: A LL edge is good if you can put the yellow sticker on the U-Face with RULD only. (without using y/y' of course)
The best thing that can happen is that all F2L edges are good after the cross is solved, because then you don't need any y-moves for F2L (see paragraph 1). Thus it is an advantage if you can turn bad edges into good edges. This happens if you use the sledgehammer (R' F R F' and mirror) sometimes instead of the standard insertion. This is because F (and B) moves also change Edge orientations. Set your cube up with a sexy move. If you insert the pair now with a sledgehammer the FR-Edge and the UF-Edge will change the orientation, all others won't. So if you build a pair during F2L and just have to put it in, think about if you want to use the sledhammer.
You always use it if both FR and UF Edges are bad, also considering LL edges.
If both edges are F2L edges, but only one is bad, it doesn't really make sense to use the sledehammer. You can do it if it is faster in your situation or if you take the next pair into consideration.
If both are good F2L edges you obviously don't use the sledgehammer.
If there is a F2L edge and a LL edge, I recommend to use the sledgehammer if the F2L edge is bad and to not care about the LL edge. Of course it also depends (maybe you can have all LL edges oriented or avoid a dot case), so sometimes it makes sense to use the standard insertion here.
If someone knows a fast way to do the sledgehammer on the Back please let me know
4. Use sexy Algortihms that involve F or B moves
There are a few algorithms that are fast despite they have F moves. For example:
Setup: Inverse of Solution
Solution: F' L' U L F R U R'
and mirror.
You can use those algorithms or a y-move + RULD solution depending on the next cases. You can control edges with them. Observe, find out when you want to do which algorithm, similar to the sledgehammer.
5. There is more than one cross solution
Simple idea: Next time you see two obvious cross solutions and think "Well that doesn't matter", think about how it changes F2L edges. Choose the solution with the most good edges as a result. Also use u-Moves to solve a pseudocross since it involes a y.
6. Combine stuff, practise
Now you know several things about EO and edge control and how it affects your F2L. Think about what is the best to do in specific situations, your skill at this will become better with time. You have to practise and always be aware of what you are doing. What does make sense, what does not?
Don't be on a rail track, fly instead.
Cheers,
Erik not Akkersdijk
Hello you cubers out there.
My name is Erik not Akkersdijk, living in Germany and 18 years old. I've never written an article about anything, so please don't yell at me. This is meant to be read by cubers who are still having trouble with bad F2L solving. Experienced cubers will hardly find anything new, but you may want to take a quick look if you missed something on your way.
I don't know how useful this will be. If I get positive reactions I will consider writing about other topics, too. If not, then at least I have collected some thoughts for myself.
I want to introduce you to Edge Orientation (EO) during F2L. Ever asked for advice on your video performance? A common reaction is "You make too many rotations". So there you are. But how exactly do you avoid them? In this little essay I want to explain some things you can do about rotations.
The first paragraph is about avoiding rotations without using edge control. It is simply about finding out which cases can be solved without F/B or y/y' in general. It also explains what good and bad edges are and how you recognize them, you will need that for the other paragraphs. Don't be afraid of learning about edge control and good/bad edges, it is not difficult. I promise.
1. Avoiding rotations by using R,U,L,D moves only
A good question is: What causes rotations? Roations are made to avoid awkward F and B moves. That means, every time a cuber feels the need of using F or B moves, he makes one or more roations to avoid them. A good first step is being aware of which cases can be solved rotationless with neither F nor B moves. So you can figure out the RULD solution for these cases and never make a rotation for those again.
So: Which cases can be solved with RULD only?
Here is a definition: A F2L case can be solved with RULD moves, if the edge of the pair is oriented correctly. If an edge is oriented correctly let's call it "Good edge", otherwise we call it "Bad edge". So we better use the following rule of thumb:
A F2L cases can be solved with RULD moves, if the edge of the pair is good.
It is a piece of cake to recognize if an edge is good or bad. Put the edge anywhere except the M-slice. If the R/L Sticker matches with the centerpiece or the opposite centerpiece the edge is good. If not, it's bad. You will be able to tell immediately if any edge is good once you are used to it.
Note: When you do y or y' the orientation of all edges in the U-Layer change, but the orientation of the edges in the E-Layer keep the same. A y2 changes nothing.
What you should do now is to figure out on which RULD cases you are still doing y-moves. These rotations are 100% unnecessary. Figure out the RULD solution for these cases to avoid a huge amount of y-moves during your solves. You can look up good algs on speedsolving wiki if you want to.
This is the easiest thing you can do to avoid roations. Everytime you notice you did a y-move on a good-edge-pair, find out the RULD solution for the next time.
2. Choose wisely when you use y and y' - Choose which pair you better solve next
This is a simple idea explained quickly. Imagine you have two good and two bad edges after the cross. What you want to do is to make first both good edges, then use y/y' only once to turn the other edges into good ones and solve them. Otherwise you are going to use y more than one time, which costs you time. Keep in mind that y/y' does not change an EO of the edge is in the E-slice. For example you can wait with good E-slice edges till the end. And if a bad edge is in the E-slice, you should put the edge out before you use y/y' otherwise you are going to do two rotations. Play around with it and you will get better with time.
You should tend to use y in a way that the solved slots are on the Back side for better look ahead.
3. Avoiding rotations by using sledgehammers
You need this little information: A LL edge is good if you can put the yellow sticker on the U-Face with RULD only. (without using y/y' of course)
The best thing that can happen is that all F2L edges are good after the cross is solved, because then you don't need any y-moves for F2L (see paragraph 1). Thus it is an advantage if you can turn bad edges into good edges. This happens if you use the sledgehammer (R' F R F' and mirror) sometimes instead of the standard insertion. This is because F (and B) moves also change Edge orientations. Set your cube up with a sexy move. If you insert the pair now with a sledgehammer the FR-Edge and the UF-Edge will change the orientation, all others won't. So if you build a pair during F2L and just have to put it in, think about if you want to use the sledhammer.
You always use it if both FR and UF Edges are bad, also considering LL edges.
If both edges are F2L edges, but only one is bad, it doesn't really make sense to use the sledehammer. You can do it if it is faster in your situation or if you take the next pair into consideration.
If both are good F2L edges you obviously don't use the sledgehammer.
If there is a F2L edge and a LL edge, I recommend to use the sledgehammer if the F2L edge is bad and to not care about the LL edge. Of course it also depends (maybe you can have all LL edges oriented or avoid a dot case), so sometimes it makes sense to use the standard insertion here.
If someone knows a fast way to do the sledgehammer on the Back please let me know
4. Use sexy Algortihms that involve F or B moves
There are a few algorithms that are fast despite they have F moves. For example:
Setup: Inverse of Solution
Solution: F' L' U L F R U R'
and mirror.
You can use those algorithms or a y-move + RULD solution depending on the next cases. You can control edges with them. Observe, find out when you want to do which algorithm, similar to the sledgehammer.
5. There is more than one cross solution
Simple idea: Next time you see two obvious cross solutions and think "Well that doesn't matter", think about how it changes F2L edges. Choose the solution with the most good edges as a result. Also use u-Moves to solve a pseudocross since it involes a y.
6. Combine stuff, practise
Now you know several things about EO and edge control and how it affects your F2L. Think about what is the best to do in specific situations, your skill at this will become better with time. You have to practise and always be aware of what you are doing. What does make sense, what does not?
Don't be on a rail track, fly instead.
Cheers,
Erik not Akkersdijk
