Want to solve the 4x4 faster? You don't need a pile of new algorithms. Most of your time goes on the moments when your hands stop while you hunt for the next piece. This post collects tips for every step of the reduction method: centres, edge pairing, the 3x3 part and parity, and every algorithm comes with a before and after picture.
It's for you if you can already solve the 4x4 from start to finish. If not, read how to solve the 4x4 for beginners first.
How to read the pictures. Each picture shows two cubes: before and after the moves. The pieces that matter are in colour, everything else is grey. You can only see the top, front and right faces.
How fast is "fast" on a 4x4?
J Perm gives an easy yardstick: once you're fairly good at the 4x4, it takes you about four times your 3x3 time. For example, if your 3x3 average is 15 seconds, your 4x4 should be about one minute (J Perm).
Compare your 4x4 time with that number. If you're a lot slower, the extra time is almost always in the centres and edge pairing, because you've already practised the 3x3 part. A simple way to check: time each part separately over a few solves, then put your effort into the slowest one.
Centres: plan from the start
- You start with (input)
- After the formula
- Look ahead to the second centre. While you build the first centre, keep an eye on where the stickers of the opposite centre are. J Perm calls this "influencing" the second centre while you work on the first.
- Pair whole bars, not single stickers. In the picture above, the top and front faces each have a yellow bar in the right column. Rw U2 Rw' puts both stickers into the centre at once, and the white centre underneath stays untouched.
- Use half-centres when they're already there. According to J Perm, if the cube already has a few half-centres (two stickers of the same colour side by side), building the last four centres from half-centres is very fast, because you only need Rw, R and U. If there aren't any, don't try to make them.
- You start with (input)
- After the formula
The last two centres are where most people get stuck. The picture above is the nicest case: each face has one red bar and one green bar standing upright, and Rw U2 Rw' swaps the two bars so both centres are done. The other cases, each with its own picture, are in how to solve the 4x4 centres. Recognising them on sight will save you more seconds than any other centre tip.
Edge pairing: look ahead to the next pair
Edge pairing is the step where it's easiest to freeze. Every time you finish an edge pair, if only then you start searching for the next pair, your hands will stop. The trick is to find the next pair while you're still doing the algorithm.
The usual pairing algorithm and its mirror
- You start with (input)
- After the formula
This is the edge pairing algorithm from the beginner guide. The top half of the front-left edge and the bottom half of the front-right edge belong to the same edge. The top-right edge holds two unpaired pieces. Uw' R U R' Uw pairs the edge and stores it in the top-left edge.
- You start with (input)
- After the formula
If the two halves are the other way round (top half at front-right, bottom half at front-left), don't turn the whole cube to swap them. Do the mirror Uw L' U' L Uw' instead: the edge gets paired and stored in the top-right edge, and the top-left edge must hold two unpaired pieces. Knowing both versions saves you one cube rotation per edge pair.
Where do you look ahead? While your hands do R U R' (or L' U' L), let your eyes find the next pair on the top and bottom layers. J Perm suggests turning just slowly enough for your eyes to keep up, especially during edge pairing. A smooth solve with no pauses is usually faster than a very fast one that keeps stopping.
Pairing several edges before fixing the slice
Once you're comfortable, fast solvers don't fix the middle slice after every edge pair. The Speedsolving.com Wiki calls this freeslice: you pair several edges in a row while the middle slice is still out of place, and only fix it once a whole batch is paired. According to that page, the most common way to do it on the 4x4 is 3-2-3: pair three edges, then two, then three (Speedsolving.com Wiki). Every step of 3-2-3, with pictures, is in the Yau method for 4x4.
One more small tip from J Perm: while pairing edges, remember where a few of the edges you'll need for F2L are. Your 3x3 step will then start faster.
Last two edges
When only two edges are left unpaired, there are no spare pieces to swap in, so you need special algorithms. J Perm says the 4x4 has only four last-two-edges cases. Below are the two you'll see most often. Put the two edges at front-left and front-right, then compare with the pictures.
- You start with (input)
- After the formula
The two top halves make one edge and the two bottom halves make the other. The front face is all green, so look at the right face of the front-right edge: in the picture it's red on top and orange underneath. Do Uw' R U R' F R' F' R Uw.
- You start with (input)
- After the formula
Again the two top halves are one edge and the two bottom halves are the other, but the colours on the right face of the front-right edge are swapped: orange on top, red underneath. Do Dw R F' U R' F Dw'. This algorithm moves a few other edge pairs around but doesn't break any of them, so it does no harm.
A quick way to tell them apart: look only at the two stickers on the right face of the front-right edge, then compare with the two pictures. Just remember "which picture" it is, no need to read the description again.
The 3x3 part: solve it like a 3x3, but rotate less
A 4x4 is heavier and harder to turn than a 3x3, so every whole-cube rotation costs more time. From this step on you only use the outer layers, exactly like the 3x3 guide. If you already use F2L on the 3x3, use it on the 4x4 too. According to the Speedsolving.com Wiki, the reduction method is all about turning the big cube into a 3x3 and then solving it as usual (Speedsolving.com Wiki).
- You start with (input)First layer all correct
- Result you will get after finishing this stepFirst two layers all correct
Parity: spot it early, solve it fast
With the reduction method, you can't avoid parity. The Speedsolving.com Wiki estimates that each of the four possibilities (no parity, only OLL parity, only PLL parity, both) happens about 25% of the time (Speedsolving.com Wiki). What you can save is the time it takes to spot it and the time it takes to do the algorithm. How to recognise each type is in 4x4 parity.
OLL parity: the Lucas Parity algorithm
- You start with (input)
- After the formula
Rw U2 x Rw U2 Rw U2 Rw' U2 Lw U2 Rw' U2 Rw U2 Rw' U2 Rw'
The Speedsolving.com Wiki calls this algorithm Lucas Parity and says it's the most popular OLL parity algorithm in speedsolving. It only uses Rw, Lw, U2 and one cube rotation x, so your hands turn smoothly and faster than with the middle-slice algorithm from the beginner guide.
Hold the cube with yellow on top and the flipped edge pair at top-front. The algorithm flips that edge pair. It also swaps the top-left and top-right edge pairs and twists the two top-front corners (the picture shows all five of these pieces), but only on the top layer: the two lower layers and the centres stay as they were. After the algorithm, look at the top face again and do the yellow face step as usual. Watch out for the x in the third move: after it, the old front face becomes the top, and you keep this new grip until the end of the algorithm.
Spot it sooner. J Perm suggests checking for parity while you do your last F2L slot: count the top-layer edge pairs that have yellow facing up. An odd number means OLL parity. Knowing in advance means your hands don't have to stop after F2L.
PLL parity
- You start with (input)
- After the formula
2R2 U2 2R2 Uw2 2R2 2U2
This is Chris Hardwick's algorithm, which the Speedsolving.com Wiki says is the most common way to solve PLL parity: it swaps the top-front edge pair with the top-back edge pair and doesn't touch any other piece. It's only 6 moves, so practise it until your hands do it on their own.
Pick an easier PLL. J Perm's suggestion: once you see you have PLL parity, choose how to hold the cube so that what's left is an easy PLL. If the corners are already in place, aim for a U perm. If two neighbouring corners need swapping, avoid the F perm and G perms. If two diagonal corners need swapping, aim for a Y perm.
A suggested practice plan
- Time each part over a few solves every day. Centres, edges and 3x3 separately. Practise the slowest part first.
- Go slow to look ahead. Do a few solves each session and try not to stop your hands even once, even if you turn slowly.
- Get the last two edges and Lucas Parity down using the pictures. Look at the picture, do the algorithm, and repeat until you recognise the case straight away.
- Compare with the 4x your 3x3 yardstick. Once you're close to that number, that's the time to move on to the Yau method for 4x4.
Sources
Frequently asked questions
Is there a way to avoid 4x4 parity?
Not with the reduction method. Parity is decided while you do the centres and edge pairing, when you can't see it. Fast solvers just spot it sooner and do the algorithm faster.
Should I switch to the Yau method right away?
Switch once you can solve smoothly with the reduction method. Yau changes the order of the steps so you don't have to flip the cube over while pairing edges, and every tip in this post still works with it.
When should I use Lucas Parity instead of the old algorithm?
Once you know the OLL parity algorithm from the beginner guide by heart and want to do it faster. Lucas Parity has more moves, but it only uses two-layer turns, so it's easier to turn quickly.
Will a better 4x4 help me solve faster?
Yes, but less than you might think. A smooth cube locks up less often, but most of your time still comes down to looking ahead and stopping less.
Cover photo: Mike Gonzalez (TheCoffee) / Wikimedia Commons, CC BY-SA 3.0