List of all F2L Open-slot and Stuck Pieces Algorithms?

FiWiFaKi

Member
Joined
Dec 5, 2016
Messages
8
Location
Canada
Hey guys, so I notice a lot of people spending most of their learning on the LL, which in my opinion has very little improvement to be had after learning OLL/PLL (like 2% improvement to average time). Stuff like COLL, ZBLL, VLS, HLS, MGLS, WV (somewhat useful), etc... Either way, my opinion is that improving the last layer comes from things like PLL 2-side recognition, etc.

Where I really see all the improvement to be had is in the F2L (and to an extent performing the extended cross)... And from what I've been able to find, the resources really suck. People like Cyo make advanced F2L videos, and they don't help me at all, since there's absolutely no organization to the algorithms he spits out you. He is talking about algorithms that are parts of huge 200-800 algorithm sets without any structure, nobody can reasonably learn like this. Almost all cubing videos about F2L techniques follow this type of format, and it's just not useful for me.

So, one website that kind of does what I ask is cubeloop.com, however my issue here is from what I can see is they go out of their way to not do any double layer turns, or any M,E,S turns, which I think hurts the efficiency of those algorithms quite a bit. I myself still don't know how to find algs with double layer turns, as Cube Explorer doesn't support it.

Empty Slot F2L Set

The way I see it is that there are 42 standard F2L algs (one of those solved), and then for each one of those cases there's an algorithm for slot to the left open, slot to the right open, and back slot open (assuming you're holding the cube such that the slot you're trying to solve is in front of you, ie normal grip, then turning cube 45 degrees CW). Then there is all the combinations of those, left + right, left + back, right + back, and also all slots open.

So in total we have 42*8 ESF2L algorithms = 336 (8 of those solved cases). Out of those, I think as a starting point, I think you want to deal with single-empty slot algorithms first, which would narrow down the algorithm count to 42*4 - 42 (the ones we already know) = 126 1ESF2L. Then there's some obvious stuff like the 4 easy F2L cases will always be the same, so that's 12 less algorithms there, and bam, down to 114 empty slot algorithms. Furthermore, I would expect... Say only 50%~ of those 114 algorithms to be actually superior to doing the regular algorithm. For example, I think to switch to a ESF2L algorithm, I would require it to be 2 moves shorter if fairly fingertrick friendly (relative to the standard F2L alg), or 3 moves shorter if kind of awkward to do. But either way, there'd be a really nice structure to it, and some 50-60 new algorithms to learn. To me this seems like the obvious choice forward after learning Full CFOP, but it seems like that's not where most people go, and because of that, I'm having trouble finding some resources. And then we have the other set of algs which I find to be very useful:

Stuck Pieces F2L Set

Now this is really just an extension of classic F2L, and if we consider every single case, I think we would have somewhere in the mid thousands (an edge can be in any of the 8 spots in any orientation, and a corner can be in any of the 8 spots in any orientation, versus 5 spots for the other.) As a first order approximation, I'd estimate there to be roughly: 8/5 = 1.6, so (336^1.6)/2... 5,500 cases. 336 because the number of EOF2L cases, divided by 2 to roughly account for not having all slots available for all the cases (like classic F2L), and to the power of 1.6, because generally speaking, I've seen a bit of a trend where something of double complexity in a rubik's cube requires x^2 cases to perform.

However if we isolate our problem to only dealing with pieces stuck in one other slot, plus the one we're trying to solve (we wont have a corner stuck in the FL and edge stuck in the BL if we're trying to solve the FR slot) there's way fewer cases. It's not natural to try and solve a block that has both pieces stuck in different slots, I don't have some mathematical proof, but I believe the percentage chance that you have 0 F2L pairs that cannot be done this way (or the normal F2L way) IF you did an extended cross is 0%. If you didn't do an extended cross, I suppose there are some odd and extremely rare F2L setups where this can happen (such as a FR slot having a piece in FL and BR, BL slot having a piece in FL and BR as well, FL having a pieces in FR and BL, and BL having pieces in FR and BL as well)... But the number of cases here can quite literally be counted on one hand.

The advantage here is that you'll never need to do a "2 look" for an F2L pair, where you have to pop it out, and then inspect what to do. Sure, there's some cases you can do intuitively, but again, it's the difference between algorithmic and intuitive F2L, where imo algorithmic is superior in the speed department as there's no thinking involved.

In total I count 90 algorithms (30 of those are mirrors though), 30 algorithms each for of the left slot relative to the one you're solving, the right slot, and the back/diagonal slot. (http://cubeloop.com/?page_id=366 is a complete set for the left slot, however not using any double layer or middle layer turns). Some of these might not save many moves, but surely some are worth learning if optimized. Many of my solves I find myself not having any pairs to solve at the start of my F2L, and having to do a RUR' or R'U'R to pop some pieces out, then having to inspect what to do. So 90 algorithms in the 1SPF2L subset.

F2L Case #1-#4 From All Positions

Pretty basic, but obviously case #1 to #4 in F2L are way easier than any other case, and because of that, you'll do these cases first... Which means you'll be doing them a lot more than any of the other F2L cases. Which makes it fairly useful I think to be able to solve them from any orientation. up face orientation, and any angle slot insertion in the most efficient way possible. Fairly intuitive, but I would appreciate having an algorithm sheet for these, so I can minimize my cube rotations and do the most fingertrick friendly move every time.

I suppose that there's 16 cases for each of the F2L cases (4 up face orientations, and 4 different locations where the slot you're trying to insert into)... So in total, 64 different cases with algorithms, but again, these are all going to be 3-5 move insertions, so not that bad - and heck, they're all very intuitive anyway.

Outside of that

I agree with Badmephisto where he says that multislotting is quite a difficult thing to do, requires a lot of on the spot thinking and computation, and unless you're someone super super dedicated and talented, the identification time to save a couple of moves isn't worth it. Partial edge control imo is not really worth it, as the dot OLL's really aren't hard compared to the others imo. Full edge control without ZBLL is also useless imo. VLS+HLS.... meeeh I think it's useless. You're saving a 3 more insert which you already were in the flow for, you're not saving any looks whatsoever... For what? The average VLS is as long as an OLL, but you're saving that insert. HLS is about the same. Saving those 3 very finger trick friendly moves versus recalling 400+ or 800+ algorithms? Not worth. Using it for some very easy cases... Meeeeeeh. Okay, I guess. But that inspection time you're spending when you might get a case you don't even do, overall, I'm just not a fan.

The only other F2L method that imo can compete with what I'm proposing would be a method that does full edge control with the 2nd and 3rd pair, and then WV for the last pair, but even that I'm not so sure about. Summer variation requires 9.4 HTM, which is roughly the same as OLL... So once again, all you're saving is that 3 move insert... However, you're likely losing those moves anyway while adding a couple extra moves to get that full edge control in your previous pairs.

Anyway, so that's what I'm looking for, the 64 algorithms for every insertion of the #1-#4 F2L cases, optimized algorithms for the 90 cases of 1SPF2L, and the 336 algorithms of ESF2L, of which I'd like to take some of the best ones in the 1ESF2L subset. Do they exist? Please and thank you.

edit: Oh, I should have mentioned, my only goal is to solve a 3x3x3 in as little time as possible, minimizing moves or whatever isn't my objective. That hopefully was clear in the post though.
 
They're on Algdb.net

Though I think you're missing the point of F2L. It's not supposed to be a huge alg set which you're supposed to learn and learning it in that way will end up being slower than the intuitive because you have to pause to recognise (in a way in which you wouldn't have to for intuitive solving) and quite frequently with multislotting you save many more than the few "fingertrick friendly moves" and also quite frequently a rotation- while you said that you don't really care about minimizing moves, I think you've missed the point that if you have fewer moves, you will in general be faster (and as I’ve said before, you're sacrificing efficiency, increasing recognition time and adding rotations all of which will slow you down).

The algs which people like chris post are not really algs so much as showing another way of doing things which can be generalised to many other cases which might be nicer in some cases but not as nice as in other cases.

I also think you're being much to dismissive of all the techniques as well. If you want to solve in as little time as possible, you will need to learn at least a few tricks like them (especially F2L). I don't think there is one truly world class cuber who can claim not to sometimes use at least some of the technique (perhaps not in full but at least in part when it might be useful).
 
The one you posted has only 41 F2L's, that's not what I'm looking for (those treat all the other slots as solved, not sure if you read my post).

I've learnt all my F2L's my intuitively going about why and how they work, but having the algorithm to fall back on. Muscle memory does all the work, but the algorithm is kind of what's written in the brain in case there's a slight delay. You need to be able to do every F2L case blind, and so intuitive and algorithmic, really become the same thing after a certain point. So anyway, I disagree with mostly everything you said unfortunately. Also I think it's silly going intuitive for every algorithm from the start, because then you'll dedicate a movement to muscle memory that isn't efficient. For example, F2L #21 and #22 have those elegant 5 move solutions that you might not otherwise do. Learn the most efficient algorithms, intuitize(not a word but yeah) them, and go from there.

I see time savings in having more algorithms for more of the F2L cases, which people are doing anyway by watching advanced F2L videos... Except they are watching them with no structure, they're just getting algorithms thrown into their face without any data systems in their mind being created.

I disagree with you in saying that you need the other techniques. My perspective is that if Feliks did not do COLL, VLS, or any other LL strategy that I criticized there, and just did his cross the way he normally does it, and did F2L way the way I'm mentioning here with his amazing look-ahead, his average times would not worsen by more than 2% (which would put him in a comfortable 2nd fastest solve ever).

I'm not into competing, I just enjoy solving the cube and want to be as fast as possible with roughly 30 minutes of daily solving. So marginal gains achieved through massive algorithm sets aren't practical for me, because they would slow me down instead of speed me up without enough practice. This F2L stuff I am looking for I think can actually make me faster without a massive amount of work.

My view from reading these forums has always been that people think that more is always better, or that it can't hurt you. And I disagree with that greatly. If you want to appreciate the puzzle more or whatever, sure. But reading things like oh, you need to learn to solve with Petrus, Roux, ZZ, and CFOP before you decide on a method... Just makes me very sad to read.

Anyway, I'm not looking to have my F2L philosophy questioned, I came here to ask if these alg sets exist.
 
Last edited:
Yeah, I don't know why there's a lack of resources for pairs like this. I genned some recently and there were some interesting solutions.
 
Yeah, I don't know why there's a lack of resources for pairs like this. I genned some recently and there were some interesting solutions.

How did you generate them? I wouldn't mind doing some of this myself... But I don't know of any other resources besides Cube Explorer, and it's a software that has so much potential but falls short in this F2L algorithm generation. Not having double layer turns is a big problem of course, and one other thing that really stands out to me is:

I wish it had some kind of weighted turn metric... Like a R or U turn is worth 1 turn amount, but an R2 turn is worth 1.2 turns (or whatever you want it, point is R2 takes a tad longer than an R)... B turns are worth more than say U turns, etc. Then being to denote values to certain fingertrick friendly sequences... It would make sorting through these algorithms and finding what's good a lot better.

I suppose it's a program that I would be able to create in Matlab, but I haven't been doing a whole lot of programming recently... And I'd rather not reinvent the wheel if it already exists somewhere.

Nice to see someone else who's been thinking about the same thing :)
 
I'm not into competing, I just enjoy solving the cube and want to be as fast as possible with roughly 30 minutes of daily solving. So marginal gains achieved through massive algorithm sets aren't practical for me, because they would slow me down instead of speed me up without enough practice. This F2L stuff I am looking for I think can actually make me faster without a massive amount of work.
Many people (myself included) who go to or intend to go to comps only practise about that much, often even less. However, what you just described is a truly huge alg set which is larger that most people would want to learn and then you have the deciding which case is better and similar so in the not too long run (around 6 months I would estimate if you progress at roughly the same speed as me) you would actually be harming your progress.

I agree with the idea that at some point algs and intuitive (for F2L and LSE at least) become almost the same though algs will frequently improve slower as the recognition hurdle is harder to overcome that to simply turn faster for intuitive.

Also, wide turns would not really help in most cases as you would have to end with basically a sledge. Most people also end up doing wide moves in various algs (not just in F2L) as they find they can execute them quicker even if they didn't exactly learn it that way,

If you don't want to take this as criticizing your "F2L Philosophy" then take it as an explanation as to why these alg sets aren't widely distributed.
 
How did you generate them? I wouldn't mind doing some of this myself... But I don't know of any other resources besides Cube Explorer, and it's a software that has so much potential but falls short in this F2L algorithm generation.

I used CE. I would just sift through the first few algs. Anything too long will probably be worse than what you use already
 
I wish it had some kind of weighted turn metric... Like a R or U turn is worth 1 turn amount, but an R2 turn is worth 1.2 turns (or whatever you want it, point is R2 takes a tad longer than an R)... B turns are worth more than say U turns, etc. Then being to denote values to certain fingertrick friendly sequences... It would make sorting through these algorithms and finding what's good a lot better.

I suppose it's a program that I would be able to create in Matlab, but I haven't been doing a whole lot of programming recently... And I'd rather not reinvent the wheel if it already exists somewhere.

It exists! It's not perfect, but trying to determine whether an alg is execution-friendly is a pretty hard problem anyway.
 
Many people (myself included) who go to or intend to go to comps only practise about that much, often even less. However, what you just described is a truly huge alg set which is larger that most people would want to learn and then you have the deciding which case is better and similar so in the not too long run (around 6 months I would estimate if you progress at roughly the same speed as me) you would actually be harming your progress.

I agree with the idea that at some point algs and intuitive (for F2L and LSE at least) become almost the same though algs will frequently improve slower as the recognition hurdle is harder to overcome that to simply turn faster for intuitive.

Also, wide turns would not really help in most cases as you would have to end with basically a sledge. Most people also end up doing wide moves in various algs (not just in F2L) as they find they can execute them quicker even if they didn't exactly learn it that way,

If you don't want to take this as criticizing your "F2L Philosophy" then take it as an explanation as to why these alg sets aren't widely distributed.

Well it's 90 algorithms for the stuck pieces with 30 of them being mirrors, of a move length of 6-7 HTM average I believe... That's probably easier than learning WV+SV, which I thought quite a few people do. And then, out of that 126 move set for the open slots, I'd imagine that it would be like 50 algorithms that average 5-7 HTM, and the rest not being worth it... That's easier to learn than COLL imo. So sure, it's plenty more to learn, but I enjoy doing it, and at the very least, I'd like to see what the optimal algorithms look like, and decide to see if it's worth pursuing.

@xyzzy Just took a look at it, and hmm, indeed very nice. For sure I'd like to see how the options alter the criteria, but definitely should do a good job weeding a lot of bad algs out, and give you a smaller group of algs to look through. I'll take a look at the source code to see if I can make any sense of it, and maybe alter it to fit it to my preferences.

@AlphaSheep Eek, I just went through the first 3 pages on that page you linked, indeed it does a lot less user friendly. I'm heading to bed for the night, but I'll take a closer look at that software tomorrow, thanks.
 
Well it's 90 algorithms for the stuck pieces with 30 of them being mirrors, of a move length of 6-7 HTM average I believe... That's probably easier than learning WV+SV, which I thought quite a few people do. And then, out of that 126 move set for the open slots, I'd imagine that it would be like 50 algorithms that average 5-7 HTM, and the rest not being worth it... That's easier to learn than COLL imo. So sure, it's plenty more to learn, but I enjoy doing it, and at the very least, I'd like to see what the optimal algorithms look like, and decide to see if it's worth pursuing.

@xyzzy Just took a look at it, and hmm, indeed very nice. For sure I'd like to see how the options alter the criteria, but definitely should do a good job weeding a lot of bad algs out, and give you a smaller group of algs to look through. I'll take a look at the source code to see if I can make any sense of it, and maybe alter it to fit it to my preferences.

@AlphaSheep Eek, I just went through the first 3 pages on that page you linked, indeed it does a lot less user friendly. I'm heading to bed for the night, but I'll take a closer look at that software tomorrow, thanks.

FR stuck in FL

https://docs.google.com/spreadsheets/d/1bqKEKg1kIsqcj5fbbX1tyNgdg3ChPSxynMQ2YYbeSks/edit#gid=0
 
Last edited:
Thank you Obelisk, that's very nice.

Hmm, of those 24, that's a 7.58 HTM, I think F2L is around 7.5 per pair. So for a stuck piece, you're going to have to pop it out, which is 3 moves, then orient top layer to start the algorithm if you will, but you have to do that in this case as well. So you're essentially saving 3 moves per stuck piece, that's pretty good I think. Considering what, you have one stuck piece on average per solve? Where you have to pop a piece up before you can do a pair.

There's 6 cases not there though. I wont lie, I thought that they'd be a bit shorter on average. Especially those 9 and 10 move ones, not really sure if they're worth knowing. Some, especially those 6 out of 24 that are 6 moves or less look really nice and handy.
 
Back
Top