How to solve a 4×4 cube
Turn the 24 centre pieces and 24 wing pieces into six centres and twelve paired edges, then finish the puzzle using the 3×3 method you already know.
Before you begin
This tutorial assumes that you can already solve a 3×3. A 4×4 has no fixed centres and each apparent edge is made from two separate wing pieces, so the first objective is to reduce it into something which behaves like a 3×3.
The grey stickers in the diagrams are irrelevant to the current step. Concentrate only on the coloured pieces shown.
Solve the six centres
Goal: six 2×2 blocksBegin with one centre
If you have solved a 3×3 before, making the first 2×2 centre should be intuitive. Choose a colour—white is convenient—and bring its four centre pieces together.
Build the opposite centre
Next solve the opposite colour, yellow if you started with white. Keep the completed first centre intact while inserting the remaining pieces.
Insert a separated 1×2 bar
With the two matching pieces aligned as shown:
Rw U2 Rw'Insert the second bar
When the pieces are positioned like this:
Rw U Rw'Solve the third centre
Hold the two completed opposite centres on the left and right. Place an existing 1×2 bar on the left of the front face, build the other bar and join them without destroying the first two centres.
Rw' U' Rw U' Rw'Show notation images
Protect a solved centre underneath
The fourth centre uses the same bar-building idea. If another completed centre is underneath the insertion area, move it out of the way, insert the new bar and restore the protected centre:
U2 Rw U2 Rw'Show notation images
Use the same bar technique for the remaining centres. Outer-layer moves do not disturb completed centre blocks, so use them freely to reposition your working pieces.
Pair the twelve edges
Goal: twelve paired edgesEach 3×3-style edge on a 4×4 consists of two wings. Find a wing in the middle layer, locate its matching partner and place that partner on the opposite side of the inner slice.
- Bring the matching wings into the working slice.
- Join them with Rw or Rw'.
- Move the new pair into a free storage slot on the left or right.
- Never overwrite a slot which already contains a completed edge.
The eight slots around the left and right layers can hold your first eight completed pairs. The remaining four edges are then solved using controlled flips or cycles.
Example: pair a green–orange edge
The first green–orange wing is on the left of the middle layer and its partner is on the right.
- Insert the partner into the right side of the working layer with U R U'.
- Join the wings with Rw'.
- Store the completed edge in a free right-hand slot with U' R U.
U R U' Rw' U' R UShow notation images
Final-four edge cycle
The visible green wing belongs with orange, while the other green wing belongs with red. Take the rear edge out, slice the green–orange wing upwards, replace the completed green–orange pair with the green–red wing and restore the slice.
U R' U' Rw R' F R F' Rw'Show notation images
Last two edges: slice–flip–slice
Sometimes the final two pairs cannot be completed by an ordinary cycle. Place both unsolved edges in the top working slice, with matching colours on opposite sides as shown. Slice, flip one wing and restore the slice:
Rw' U' R' U R' F R F' RwShow notation images
Solve the reduced cube as a 3×3
From this point, treat each 2×2 centre block as one centre and each paired edge as one edge. Use your normal 3×3 method:
- Solve the cross.
- Solve the first two layers.
- Orient the last layer.
- Permute the last layer.
Recognise and solve parity
Reduction can produce two last-layer states which are impossible on a 3×3. OLL parity and PLL parity are independent; each occurs on approximately half of ordinary reduction solves.
OLL parity
If one paired edge appears flipped—or the yellow edge pattern is not a dot, L, line or cross—hold the affected edge at top-front:
Rw2 B2 U2 Lw U2 Rw' U2 Rw U2 F2 Rw F2 Lw' B2 Rw2PLL parity
If exactly two paired edges need swapping, hold them at top-front and top-back:
Rw2 R2 U2 Rw2 R2 Uw2 Rw2 R2 Uw2