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F2L and lookahead guide - example solves - not a video.

Escher

Babby
Joined
Jul 23, 2008
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WCA
2008KINN01
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So I've been thinking of making something like this for ages and now I have to actually do some work here it is.

For brevity's sake a couple of these solves will not be my normal approach and include way more tricks, but I'll make sure a couple are genuine speedsolves.

Most of these tricks are things I've intuited, but any multislotting guides you can find and advanced f2l pages will probably have similar or the same algs.

solve 1:
(scramble WCA position)
L2 D2 R' L' F' D L2 R' D B' L2 D' B R F2 L2 D2 R2 L2 D B R2 L' F' B

Upon inspection I'm basically looking at either white or yellow and quickly checking which is better (I haven't thought or codified how I check, I just do it...), planning a safety cross (in this case D' L' D L' D2 y' U R' F R), then either looking ahead into f2l (I'll describe that process next solve), or planning an x-cross, OR creating/preserving a free pair in the U layer. At the same time as all this, I'm thinking about the moves I'm going to do and which angle they would be fastest from.

The cross in this case is D' U2 L' D' R2 U u' L u.

The U2 at the beginning connects that f2l pair, and the U means that it will end up in a relatively easy to solve position. Since I've noticed that orange/blue corner in DR, I can look around the rest of the cube for the orange/blue edge - which is revealed by that u' cross move.

Next I'll do L R2 U' L2 U L to solve both pairs. This trick combines the effects of L U' L2 U L (which inserts whatever is in the UB position), and just doing a simple R2 to join up the orange/blue pair. My favourite thing about this is that with just 2 extra moves (R2 (x) R2) you solve a case that would take at least 6 with the normal approach, and that the f2l alg for the BL pair returns the cross edge to it's correct position without any extra AUF.

I'll next do R U' R to free up that green/red pair, luckily the next pair cancels with it (though I probably wouldn't notice it and do it - it's just convenient for hand position). I'll insert it with a sledgehammer too; there are 3 misoriented LL edges and orienting them increases the chance of an OLL skip. So: R' U' R2 x' U' R' U x

Then a 3 move Winter Variation case, plus I notice that block in UFR that will be preserved - it will be any of a V, J or A perm. In this case you can actually predict it will be a V or A (but I wouldn't in a speedsolve) because this case joins up the misoriented U layer corner with the block, in UBL, and since the sticker is blue and the UR edge is green it's thus placed diagonally from it's home position.

So, U2 y L' U L. It's a V perm - U (pushing with LH index on LBU to save using the RH index and let it get into position for the R' U R') etc etc.

full solve:
L2 D2 R' L' F' D L2 R' D B' L2 D' B R F2 L2 D2 R2 L2 D B R2 L' F' B

D' U2 L' D' R2 U u' L u (9)
L R2 U' L2 U L (6|15)
R U' R (3|18) (this could cancel - R U2 R2 x' U' R' U, giving a 25 move f2l & 40 move speedsolve)
R' U' R2 x' U' R' U x (6|24)
U2 y L' U L (4|28)

U R' U R' Dw' R' F' R2 U' R' U R' F R F (15|43)

So, a pretty good solve. Whether I would do this in a speedsolve depends on how much I'm warmed up and what cube I'm using; with a very high tps I'd probably do something more standard.

Solve 2:

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

A cruel scramble on inspection.

Cross: y2 x U' R F' U R2 D x'

Notice how the order of putting cross edges in affects stuff: I could just have easily done U' R F D' U R2 and broken up that pair... Usually on this kind of cross I would never bother with looking ahead, it's just not that nice.

Since I know that pair is going to be there I can ignore it for the moment. While executing my cross I notice that the orange/blue edge is in a slot and flipped. I'll know to try and change the rest of my f2l slightly so that the corresponding corner ends up in a better position, perhaps in UBL. The corner appears after that R2 so I can go straight into it after the orange/green pair.

R U' R2 U R. Now I'm presented with a hell of a lot of options - I can either insert the made pair, or join up the red/green with four moves preserving the made pair (but 'generating' two rotations) or just carry on with what I saw earlier.

The first option is probably the best in this scenario - we can insert the made pair using F' L F L' to kick out the edge that is stuck in the FL slot (and also avoid a rotation for this particular slot), and we might be able to do something fun with the next two pairs if it's freed up. So we do:
U2 F' L F L'.

This has left us with a nice 3 move insert in FR slot (albeit with a rotation), but at the same time if you look ahead you'll see that this will leave us with a bad f2l case for the green/red pair (joined up but edge flipped), and it would be especially bad in this case since the nicest way to execute the usual alg for it (R' U2 R2 U R2 U R) is another rotation again after the 3rd pair.

So instead we use a trick from multislotting:
y' L' R' U' R
and then to setup a nice little 3 move case we insert an extra U' in there to move around the corner, and then we rotate again and insert:

(y' L' R' U' R) U' L y' U2 R U R'

And f2l is done! Luckily we've also oriented edges, which we wouldn't have using a more normal approach.

Complete f2l:

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

y2 x U' R F' U R2 D x' (6)
R U' R2' U R (5|11)
U2 F' L F L' (5|16)
y' L' R' U' R U' L (5|21)
y' U2 R U R' (4|25)

(LL is 18 moves inc AUF - 43 move solve)

Solve 3:
Scramble: L' R' U2 F B D U2 R B' U' L2 R' U2 D' R' D' L' U' F' R2 D' F' L D B'

Okay, so on this scramble I notice that if I do y2 L then I'll join a pair, so I'll try to change my cross about a bit to accomodate it.

cross: y2 L F R' D U' L* B' U R'
*at this point I notice the corresponding edge for the green/orange corner is at UB - and I know that by doing that 2nd to last cross edge it will be oriented nicely in relation to it's corner, and that by doing that extra U turn I can set up a 3 mover...

Now the situation is irritating - it looks like it has potential but I really can't see anything to solve both the BR and FR pairs at once. The best I'll do is make sure that when the orange/blue pair gets taken out it also gets broken up; I can use a nice little trick to do this:
y L R U' R' U L'

then an easy 3 move insert (that was quite predictable during that trick):
U' L' U' L

And then a cool, kinda intuitive alg for the last pair: U2 R2 U2 R U R' U R2, then a 6 move OLL and G perm (20 moves in total inc AUF).

So all together:
L' R' U2 F B D U2 R B' U' L2 R' U2 D' R' D' L' U' F' R2 D' F' L D B'

y2 L F R' D U' L B' U R' (9)
y L R U' R' U L' (5|14)
U' L' U' L (4|18)
U2 R2 U2 R U R' U R2 (8|26)

(46 move solve)

I actually have to go and do some work now - but I will edit more solves in later, along with stuff on pair prediction and making extended crosses - I just wanted to get this started and posted so that I actually would do it.

Hopefully this will inspire you to play with Fridrich f2l a bit more and see that it isn't just one spammy alg after another at all...

As soon as I can, which unfortunately will probably be around xmas, I'll make a video (plural if I cba) with more of this sort of stuff in - it's a bit easier to follow than this behemoth.

Cheers,
Rowan.

(Btw, I wrote this while still drunk/with a massive hangover so excuse typos and bad formatting for now)
 
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I know this is going to sound like a complete noob of me, but...
What is the WCA position for scrambles? Is it White on U and Green on F?

Also, when he gives the solve, which way is he holding the cube? White cross on D? Green on F?
He gives the cross, but I don't know what way I'm supposed to be holding the cube, when following that cross...
 
Very nice trix! .. thanks for sharing :tu

A couple of these multislotting tricks reminded me of some of the stuff I do in ZZF2L. Has ZZ provided any inspiration/ideas? The cool thing about taking advantage of slots in ZZ is that they don't need to be returned to their original state. When I have a 1x2x2 block I normally prefer to store it in the back position, but it may switch (regardless of where it belongs) if I need to use the slot. Also, it's nice to have 2 'non-diagonally-opposite' slots available as it allows for slot tricks to be used in any situation - this mainly applies to ZZ, but maybe also a little to Fridrich if you're trying to avoid y-rotations and F/B moves.

BTW, the moves (y L R U' R' U L') from your third solve, I find myself doing these kind of L,U,R-sequences from time-to-time, but don't like having to rapidly switch from RU-gen to LU-gen. Are there any tricks you can use to improve this, like z rotations maybe?
 
@Cride5:

Yes, I think practicing with ZZ did open my eyes a little to how Fridrich was really just restricted blockbuilding rather than just a set of cases one after another... That and learning stuff from Breandan over msn was really helpful.

I'm not sure how to solve execution problems in terms of <L, U> and <R, U> switching, perhaps adopting more of a <R, r, U> approach to L moves might be more appropriate (like in the 'lefty' J perm: x r' U' r U r' U' L U r U' r2 F r) in certain situations.
 
I haven't seen such a great thread in a while!

On the third solve, the last two pairs could be done like this:

Use the empty FL slot to your advantage to solve the green and red pair, and preserve the orange and blue easy L' U' L insert case.

By doing L' we have made the green and red pair slightly easier to solve, so:

L' (U2 R' U' R U' R' U' R)

Then to return the orange and blue pair to the easy L' U' L insert case, we simply do L.

Now we simply do U' L' U L for the last pair.

It's two more moves than your solution, Rowan, but a bit more fingertricky :p
 
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Btw I only just found out that if we solved the green and red pair normally, it would leave us with an easy L' U2 L for orange blue (11 moves in total) :p

However I didn't know this would happen, I think maybe I should learn about the effects that F2L algs have on other pieces in the future...
 
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