F2L back slot cases happen when the corner and edge pair you need to insert belongs in one of the two slots at the back. Beginners usually rotate the whole cube (y, y') to bring that slot to the front. This guide shows how to solve all 24 cases of the back right slot without rotating the cube, each with its own picture, and then how to turn them into back left slot moves.
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 follows on from Advanced F2L tips, where you met the four basic inserts for each slot. Every move sequence here was tested on the EasyRubic cube simulator.
Why solve back slots without rotating?
J Perm advises avoiding cube rotations and wasted moves as much as possible during F2L (J Perm). Every y rotation costs you a beat, and even worse, you lose track of the pieces you were watching for your next pair.
But not rotating isn't always better. Cubefreak's Advanced F2L page suggests that for awkward cases, it can be worth rotating the cube and then using a fast algorithm made only of R and U moves (Cubefreak). This guide gives you the choice: solve the cases that work neatly from the back straight away, and rotate for the ones that feel too clumsy.
How to hold the cube and read the pictures
- White face on the bottom, cross already done. Yellow face on top.
- Green face at the front, orange on the right, red on the left, blue at the back.
- The back right slot holds the white, blue and orange corner and the blue and orange edge.
- The other three slots are already solved, and every algorithm keeps them that way.
Each picture shows two cubes. The cube on the left is the case you have, with the last layer greyed out. The cube on the right is the result, flipped over so the white face is on top and you can see both finished layers.
In every case below, the corner has been moved with U so it sits right above the back right slot. You only need to check two things: which way the corner's white sticker is facing, and where the edge is and which colour faces up. If the notation is new to you, see Rubik's cube notation for beginners.
Spotting trick: look at the edge's blue sticker
This is the most important trick in this guide. Look at the blue and orange edge while it sits in the top layer:
- Blue sticker facing up: this case can be solved with only R and U, and it feels just like solving the front right slot.
- Orange sticker facing up (blue sticker on the side): R and U are never enough. You need an extra B or F move.
The reason is edge orientation. The SpeedSolving Wiki says an edge is "oriented" if it can be put back in place using only L, R, U, D, F2 and B2 moves (SpeedSolving Wiki). In other words, only quarter turns of F and B can flip an edge. The SpeedSolving Wiki's F2L page mentions this same effect when it talks about F2L using only R and U (SpeedSolving Wiki).
That is why this guide splits the 24 cases into two groups of 12, following exactly this rule.
Group 1: blue sticker facing up (R and U only)
Pair goes straight in
See it in 3D, before and after
- You start with (input)
- After the formula
Case 1. R' U' R: the corner's white sticker faces right, orange sticker faces up. The edge is at the front of the top layer. R' lifts the slot, U' brings the two pieces together, R drops the pair in.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 2. U' R' U R: the pair is already joined. White sticker faces back, edge on the right of the top layer. U' moves the pair off the right face, R' U R inserts it.
Corner with the white sticker facing right
See it in 3D, before and after
- You start with (input)
- After the formula
Case 3. U R' U' R U' R' U' R: edge on the left of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 4. U R' U R U' R' U' R: edge on the right of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 5. R U2 R2 U' R2 U' R': edge at the back of the top layer, right next to the corner but not joined.
Corner with the white sticker facing back
See it in 3D, before and after
- You start with (input)
- After the formula
Case 6. U R' U' R U2 R' U R: edge at the front of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 7. U R' U2 R U2 R' U R: edge on the left of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 8. B U' B' U2 R' U' R: edge at the back of the top layer. This case can still be solved with only R and U, but the simulator shows that way needs at least 9 moves. The 7-move sequence here uses B U' B' to pull the corner out first.
Corner with the white sticker facing up
See it in 3D, before and after
- You start with (input)
- After the formula
Case 9. R' U2 R U R' U' R: edge on the right of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 10. U' R' U2 R U' R' U R: edge at the front of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 11. R' U R U2 R' U' R: edge on the left of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 11 also has a 5-move option: R' F' U2 F R. This one uses F' and F, but the front right slot still ends up exactly as it was.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 12. U2 R2 U2 R U R' U R2: edge at the back of the top layer.
Group 2: orange sticker facing up (needs an extra B or F)
In these 12 cases, the edge's blue sticker is on the side. Every algorithm has at least one B or F move. When two options are equally short, this guide picks F, because the front face is easier to see than the back.
Two basic cases
See it in 3D, before and after
- You start with (input)
- After the formula
Case 13. B U B': the corner's white sticker faces back. Edge on the left of the top layer. This is the mirror image of F' U' F in the front right slot.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 14. U B U' B': the pair is already joined, white sticker faces right, edge at the back of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
If you'd rather not turn B, case 14 also works with U R' F' U' F R, using only R, U and F.
The R2 trick: borrow the front right slot
A half turn of R brings the empty back right slot round to the front, while the solved front right pair moves to the back for a moment. You join the pair and drop it into the empty spot at the front with F and U, then another R2 sends the pair back to the back slot and returns the front right pair to its place.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 15. R2 F' U' F U R2: the corner's white sticker faces right. Edge on the left of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 16. R2 U' F' U F R2: the corner's white sticker faces back. Edge at the front of the top layer.
Corner with the white sticker facing right
See it in 3D, before and after
- You start with (input)
- After the formula
Case 17. F R U R2 U' R F': edge at the front of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 18. R' U F' U F U2 R: edge on the right of the top layer.
Corner with the white sticker facing back
See it in 3D, before and after
- You start with (input)
- After the formula
Case 19. B' U2 B2 U B2 U B: edge on the right of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 20. U' B U' B' U B U B': edge at the back of the top layer.
Corner with the white sticker facing up
See it in 3D, before and after
- You start with (input)
- After the formula
Case 21. B U2 B' U' B U B': edge at the back of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 22. U B U2 B2 R B R': edge on the left of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 23. B U' B' U2 B U B': edge at the front of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
Case 24. U2 B2 U2 B' U' B U' B2: edge on the right of the top layer.
Cases 19 to 24 use the most B moves. This is exactly where Cubefreak's advice helps: if you're not comfortable turning B yet, rotating the cube and using a front slot algorithm your hands already know can sometimes be faster.
When the corner is stuck in the back slot
If the corner is already in the back right slot but twisted the wrong way, and the edge is in the top layer with its blue sticker facing up, you still only need R and U.
- You start with (input)
- After the formula
Case 25. R' U R U' R' U R: corner in the slot, white sticker facing back. Edge on the right of the top layer.
- You start with (input)
- After the formula
Case 26. R' U' R U R' U' R: corner in the slot, white sticker facing right. Edge on the right of the top layer.
For other stuck cases, the simplest way is to take the corner out with R' U R (or R' U' R), then solve it like one of the 24 cases above.
Back left slot: mirror it to the left
The back left slot holds the white, blue and red corner and the blue and red edge. Every case there is a mirror image of the back right slot, reflected across the plane between left and right. Here's how to change the algorithms:
- R becomes L, but the direction flips: R' becomes L, R becomes L'.
- U, F and B keep their letter but flip direction: U becomes U', F' becomes F, B becomes B'.
- Double moves (R2, U2, B2) only change the letter R to L.
The blue sticker trick still works: if the blue sticker faces up, you only need L and U. Here are five examples, each showing the original back right case it comes from.
See it in 3D, before and after
- You start with (input)
- After the formula
L U L' (from case 1): corner right above the back left slot, white sticker facing left, red sticker facing up. Edge at the front of the top layer, blue sticker facing up.
See it in 3D, before and after
- You start with (input)
- After the formula
U L U' L' (from case 2): the pair is already joined, white sticker facing back, edge on the left of the top layer.
See it in 3D, before and after
- You start with (input)
- After the formula
L U2 L' U' L U L' (from case 9): the corner's white sticker faces up, edge on the left of the top layer, blue sticker facing up.
See it in 3D, before and after
- You start with (input)
- After the formula
B' U' B (from case 13): white sticker facing back, edge on the right of the top layer, red sticker facing up.
See it in 3D, before and after
- You start with (input)
- After the formula
L2 F U F' U' L2 (from case 15): the L2 trick borrows the front left slot. White sticker facing left, edge on the right of the top layer, red sticker facing up.
Which order should you go in?
- Cases 1, 2, 13, 14 first. They are the four basic inserts, only 3 or 4 moves each.
- All of group 1 (cases 1 to 12). They use only R and U, so your hands already know the feel from the front right slot.
- The R2 trick (cases 15, 16). Easy to remember, because the middle part is exactly the front right slot insert with F.
- The rest of group 2. Practise B and B' slowly. If a case feels awkward, just rotate the cube for it; nobody says you have to give up y for good.
When you practise, keep the other three slots solved, set up the exact case by doing the algorithm backwards, then solve it again. Time yourself with the 3x3 timer to compare solves with and without rotations.
Common mistakes
- Forgetting to put the corner above the back right slot before you look. Every description in this guide starts from that position. Turn U to get it right first.
- Mixing up the direction of R at the back. In the back right slot, R' opens the slot and R closes it, the opposite of the front right slot.
- Using R and U on a case with the orange sticker facing up. You'll go round and round and the edge will still be flipped. Check the blue sticker before you turn.
- Refusing to rotate no matter what. One clean y rotation is still better than a clumsy B algorithm that makes you stop and think.
Next steps
To see all 41 cases for the front right slot, read F2L algorithms: all 41 cases. If you're new to CFOP, What is CFOP has an overall roadmap, and Intuitive F2L explains why the insert sequences work.
With the EasyRubic app, you can scan your real cube with the camera and follow the solution step by step on a 3D cube. Download EasyRubic to practise your own F2L pairs.
Sources
Frequently asked questions
What is an F2L back slot?
It means inserting a corner and edge pair into one of the two slots at the back (back right or back left) while solving F2L, instead of only using the front slots.
Is it worth solving F2L back slots without rotating the cube?
Yes, once you can solve F2L reliably. J Perm advises avoiding cube rotations as much as possible. But for a few awkward cases, rotating the cube and using an algorithm your hands already know is still a sensible choice.
How can I tell which back slot cases only need R and U?
Look at the blue and orange edge in the top layer. If the blue sticker faces up, the case can be solved with only R and U. If the orange sticker faces up, you need an extra B or F.
How many cases does the back right slot have?
When both the corner and the edge are in the top layer, the back right slot has 24 cases, the same as the front right slot. This guide has one algorithm and one picture for each case.
How do I solve the back left slot?
Mirror the back right slot algorithms: R becomes L and flips direction, U, F and B keep their letter but flip direction, and double moves only change R to L.