Advanced F2L isn't about piling on more and more algorithms. It's a set of tips that help you solve the four F2L pairs with fewer moves, fewer whole-cube turns and fewer pauses. This post gathers the five most useful F2L tips: picking the easy pair, solving the back slots without turning the whole cube, using an empty slot, keyhole, and look-ahead.
Find your case fast
Look at your cube from above and tap the picture that matches it to see how to solve it. Grey cells are stickers you can ignore.
This is part five of the CFOP series on EasyRubic, after Cross CFOP, X-cross, Intuitive F2L and F2L algorithms: all 41 cases. Every move sequence in this post was tested on the EasyRubic Rubik's Cube simulator, including the move counts we compare.
When are you ready for advanced F2L?
Come to this post once you can solve all four F2L pairs without looking at a guide, even if you're still slow. If you can't yet, read Intuitive F2L first.
J Perm suggests getting to grips with F2L by understanding why each step works, then practising until the steps feel natural, before moving on to anything else (J Perm). The same page calls look-ahead the most important idea in speedsolving for anyone aiming to get under 20 seconds. As for comparing your own solutions with optimal algorithm sheets, J Perm says to save that until you solve in roughly under 15 seconds.
Suggested order: tips 1 and 2 work right away. Tips 3 and 4 need you to be used to spotting which slots are still empty. Tip 5 (look-ahead) is something you practise over a long time, alongside everything else.
How to hold the cube and read the pictures
Throughout this post, hold the cube the same way as in the earlier posts of the CFOP series:
- White face on the bottom, cross already done. The yellow face is on top: that is layer 3 (the top layer).
- Green face in front, orange on the right, red on the left and blue at the back.
- The four slots are named by where they sit: front-right, front-left, back-right, back-left. The front-right slot holds the white-green-orange corner and the green-orange edge.
Each picture has two cubes. The cube on the left is the case you have. Only the cross, the F2L pairs and the centres are coloured; layer 3 is grey. In tips 3 and 4, the empty slot is grey too, because its pieces can be anywhere. The cube on the right is the result, flipped so the white face is on top and you can see both layers.
If you don't know the notation R, L, U, D, F, B yet, see Rubik's Cube notation for beginners.
Tip 1: pick the easiest pair first
After the cross, you have four pairs to choose from. Beginners usually solve the first pair they see. Fast solvers look at all four and pick the one that takes the fewest moves.
An easy order to remember:
- A pair that is already joined, or one you can insert straight away in three or four moves, like the basic cases in Intuitive F2L.
- A pair with both pieces in layer 3. You are free to turn U to bring them to an easy spot.
- A pair with one piece stuck in a slot. Leave it for later, because you have to spend moves pulling that piece out.
But don't save the hardest pair for the very end if you can solve it earlier using an empty slot (tips 3 and 4). While there are still empty slots, you have far more options: the SpeedSolving Wiki counts 41 cases for the last slot, but as many as 167 cases for the first slot (SpeedSolving Wiki).
Tip 2: solve the back and left slots without turning the whole cube
Turning the whole cube (y, y') takes time and makes you lose track of the pieces you're following. J Perm advises avoiding cube rotations and wasted moves as much as you can (J Perm).
The good news is that you don't need anything new. The two basic inserts for the front-right slot are R U R' (corner and edge apart) and U R U' R' (pair already joined). Every other slot has two matching inserts, with just the face and the turning direction changed.
See it in 3D, before and after
- You start with (input)
- After the formula
The picture above is U R U' R' in the front-right slot, so you can compare it with the slots below.
Back-right slot
The back-right slot uses the R face, but every move goes the other way compared with the front-right slot.
See it in 3D, before and after
- You start with (input)
- After the formula
R' U' R: the corner is above the back-right slot, white sticker facing right, orange sticker facing up. The blue-orange edge is on the front edge of layer 3, blue sticker facing up. R' lifts the slot up, U' brings the two pieces together, R puts the pair down.
See it in 3D, before and after
- You start with (input)
- After the formula
U' R' U R: the pair is already joined above the back-right slot. The corner's white sticker faces the back, both blue stickers face up and both orange stickers face right. U' moves the pair off the right face, R' U R inserts it.
Front-left slot
The front-left slot uses the L face. Compared with the front-right slot, swap R for L' and U for U'.
See it in 3D, before and after
- You start with (input)
- After the formula
L' U' L: the corner is above the front-left slot, white sticker facing left, red sticker facing up. The green-red edge is on the back edge of layer 3, green sticker facing up.
See it in 3D, before and after
- You start with (input)
- After the formula
U' L' U L: the pair is already joined above the front-left slot, white sticker facing the front, both green stickers facing up and both red stickers facing left.
Back-left slot
The back-left slot uses the L face with exactly the same turning directions as the front-right slot: just swap R for L.
See it in 3D, before and after
- You start with (input)
- After the formula
L U L': the corner is above the back-left slot, white sticker facing left, red sticker facing up. The blue-red edge is on the front edge of layer 3, blue sticker facing up.
See it in 3D, before and after
- You start with (input)
- After the formula
U L U' L': the pair is already joined above the back-left slot, white sticker facing the back, both blue stickers facing up and both red stickers facing left.
Practice tip: the back slots are harder to see because the pair is on the far side. Tilt the cube slightly towards you so you can see the back, instead of turning the whole cube.
Tip 3: use an empty slot
When another slot isn't solved yet, that slot is a free "storage space": you can open it, hide a piece in it for a moment or join the pair inside it, because there's nothing there to break. The SpeedSolving Wiki's list of links has a whole group of algorithms just for cases with an empty slot (SpeedSolving Wiki).
We had a computer search the simulator for the shortest solutions to the long cases of the front-right slot, each time treating another slot as empty. Below are two examples that use only R and U and are 3 moves shorter than the usual algorithm. The computer also confirmed that there is no solution under 5 moves for these two cases, whatever faces you use. In both, the back-right slot must still be empty.
Example 1: edge on the left of layer 3
- Corner above the front-right slot, white sticker facing right, orange sticker facing up.
- Edge on the left edge of layer 3, green sticker facing up.
This is F2L 10 in the 41 cases post. The usual algorithm is U' R U R' U R U R', 8 moves.
See it in 3D, before and after
- You start with (input)
- After the formula
With the back-right slot empty: R' U R2 U R', 5 moves.
- R': the corner drops down into the front-right slot (not facing the right way yet).
- U: the edge travels from the left to the back of layer 3.
- R2: the corner comes up at the back and joins the edge straight away. This move passes through the back-right slot, so that slot has to be empty.
- U R': brings the pair to the right spot, then inserts it.
Example 2: corner already in the slot
- Corner already in the front-right slot, white sticker facing down.
- Edge on the right edge of layer 3, green sticker facing up.
This is F2L 25. The usual algorithm is U' F' U F U R U' R', 8 moves.
See it in 3D, before and after
- You start with (input)
- After the formula
With the back-right slot empty: R2 U' R' U R2, 5 moves. The idea is to join the pair right inside the empty slot, then move the whole pair across:
- R2 U' R': the corner goes up to layer 3, and the edge is placed in the back-right slot.
- U: the corner comes back right above the edge. The pair is now joined, standing in the back-right slot.
- R2: a half turn of R moves the whole pair from the back-right slot to the front-right slot.
Careful: if the back-right slot is already solved, these two sequences will break it. Before using them, always check that the slot is still empty.
Tip 4: keyhole with a D move
Keyhole is the idea of using an unsolved slot as a door to bring a piece into place. The SpeedSolving Wiki describes keyhole as a way to solve the first two layers: leave one bottom-layer corner empty, then use that gap to insert the middle-layer edges (SpeedSolving Wiki). In F2L, you use it when one piece of the pair is already in place and the other is in layer 3.
The most common example:
- The green-orange edge is already in place in the front-right slot.
- Corner above the front-right slot, white sticker facing right, orange sticker facing up.
- The front-left slot is still empty.
This is F2L 34. The usual algorithm is U R U R' U2 R U R', 8 moves, because you have to pull the edge out and join it up again.
See it in 3D, before and after
- You start with (input)
- After the formula
With keyhole: D' L' U L D, 5 moves, and the edge never leaves the slot. The simulator found no shorter solution with the front-left slot empty.
- D': turns the bottom layer. The corner's spot moves from front-right to front-left, right under the empty slot.
- L' U L: one three-move insert into the front-left slot. L' lifts the gap up, U brings the corner across from above the front-right slot, L puts the corner down.
- D: turns the bottom layer back. The corner comes along and ends up right under its edge. The cross goes back into place too.
The D' move knocks the cross out of line for a moment, but the final D puts everything back. The edge in the front-right slot is in the middle layer, so the D moves don't touch it.
Tip 5: look-ahead, seeing the next pair early
The SpeedSolving Wiki defines look-ahead as the ability to see what's coming next, and says good look-ahead can make a solve almost pause-free (SpeedSolving Wiki). In F2L, that means that while your hands solve this pair, your eyes are already looking for the next one.
The three levels of look-ahead
In a post on CubeSkills, Feliks Zemdegs splits look-ahead into three levels (CubeSkills):
- Spotting: you only look at the pair you're solving. You only go looking for the next pair once this one is done. This is where most beginners are.
- Tracking: while solving this pair, your eyes follow the pieces of the next pair.
- Knowing: you can tell where the pieces of the next pair will end up before you even turn.
There are small steps between the levels. For example, being able to track just one piece of the next pair is already progress.
Practise knowing where pieces will go
To reach the "knowing" level, you need to picture the move sequence in your head. Start with the sequence you do most often, R U R':
See it in 3D, before and after
- You start with (input)
- After the formula
In this sequence, the R and R' moves don't touch the left half of layer 3. Only the U move shifts those pieces, by exactly a quarter turn:
- An edge at the front of layer 3 moves to the left.
- An edge on the left of layer 3 moves to the back.
- The front-left corner of layer 3 moves to the back-left corner.
So if a piece of the next pair is at the front of layer 3, you know it will be on the left after the insert, without having to watch it. Repeat this drill with U R U' R' and the inserts for the other slots.
Turn slowly, look a lot
CubeSkills gives a few practical tips (CubeSkills):
- Slow down on the last three moves of each pair, so your eyes are free to find the next one.
- Keep the cube steady in your hands, turning smoothly instead of in jerky bursts.
- Treat F2L as one smooth flow from the cross to OLL, not four separate puzzles. A steady F2L with few pauses beats a very fast F2L that keeps stopping and starting.
J Perm also suggests working out the first F2L pair during inspection, so you don't have to stop after the cross (J Perm). The X-cross post goes one step further: solving that pair together with the cross.
Predict OLL from the last pair
Once you're comfortable, look at layer 3 while you insert the last pair. CubeSkills suggests starting by predicting the yellow edges (dot, L shape or line), then moving on to predicting the whole OLL case. You'll go into OLL without stopping to look.
Drills for advanced F2L
- Solve a pair from memory. CubeSkills recommends practising each pair with your eyes closed: look at the pair, think of the solution, close your eyes, then do it. If you can, your hands are confident enough to let your eyes look elsewhere.
- Find before you turn. Do the cross, find the first pair and think of its solution. Before turning a single move, find the second pair too. Solve pair one while your eyes follow pair two. Repeat until F2L is done. This is CubeSkills' main drill for going from "spotting" to "tracking".
- Metronome. Set a metronome very slow, one move per beat, and don't allow yourself to stop. Speed it up bit by bit. The hardest parts are the jump from the cross to the first pair, and from one pair to the next.
- Empty slot hunt. In each solve, leave the hardest pair for last, and before that, try to find a solution for it that uses an empty slot.
- No rotations. Pick one practice session where you ban yourself from using y and y'. Every slot has to be solved with the inserts from tip 2.
- Time yourself. Use the 3x3 timer and keep an eye on your average of 12. When you first start turning slowly to look ahead, don't worry if your times don't drop straight away; compare your averages week by week.
Common mistakes
- Using an empty slot trick when that slot is already solved. Always check first. Breaking a finished slot costs more moves than you just saved.
- Forgetting the final D move of keyhole. Without it, the whole cross is off by a quarter turn.
- Turning faster than your eyes. If you pause for a long time between pairs, turn more slowly. CubeSkills says a steady F2L with few pauses beats a fast F2L that keeps stopping and starting.
- Reaching for advanced algorithms too early. Understand why the sequences work first, as J Perm advises. The empty slot and keyhole tricks are both just open the slot, turn U, close the slot, done in a smarter way.
Next steps
After F2L comes OLL. The What is CFOP post has the overall roadmap, and the next post in the CFOP series covers 2-look OLL: orienting layer 3 with 10 algorithms. If your hands are still slow, the post on finger tricks will help you turn more smoothly.
With the EasyRubic app, you can scan your real cube with the camera and see the solution step by step on a 3D cube. Get EasyRubic to practise your own F2L pairs.
Video
Want to see it in motion? The short video below from the RUBIK BMT channel on YouTube shows more of what this post covers. The video belongs to that channel and is embedded directly from YouTube.
Sources
Frequently asked questions
What is advanced F2L?
It's a set of tips for solving F2L faster once you know basic F2L: picking the easy pair, solving every slot without turning the whole cube, using empty slots, keyhole and look-ahead. Most of it is a way of thinking, not new algorithms.
What is keyhole in F2L?
It's a way of using an unsolved slot as a door to bring a piece into place. For example, when the edge is already in place in its slot but the corner is still in layer 3, the sequence D' L' U L D brings the corner in through the empty front-left slot.
What is look-ahead in F2L?
It's looking at and following the next pair while your hands are still solving the current one, so you don't have to stop between pairs. J Perm calls it the most important idea in speedsolving.
Should you turn the whole cube during F2L?
As little as possible. Every slot has its own inserts using R, L and U, so you can solve all four slots without y or y'.
How many moves does an empty slot save?
It depends on the case. In the three examples in this post, the empty slot solutions are 5 moves long, compared with 8 moves for the usual algorithm.