Choose an edge without yellow and decide whether its top sticker belongs left or right.
By the end: finish two layers and recover a flipped or misplaced middle edge.
Keep the solved white layer down. Find a top-layer edge with no yellow sticker. Turn U so its side sticker matches a side center, then regrip to face that matched pair. The edge is now at top-front.
Look at its top sticker. If that color matches the right center, insert right. If it matches the left center, insert left. The direction comes from the target center, not from which hand you prefer.
The middle layer contains four edges with no white or yellow stickers. Each belongs between two neighboring side centers. The white layer is already solved below, so no white edge needs to move into the middle. With yellow above white, an edge containing yellow belongs in the top layer eventually, even if its other sticker matches a side center now. Inspect both stickers before choosing a target. A top-facing sticker can be read in the U face of the net when the solid view makes its color or piece attachment unclear.
At the beginning of this stage, verify the entire white layer rather than only its face. All bottom side rows must match their centers. The insertion sequences preserve that completed layer at their ends; they do not repair earlier white-layer errors. The teaching cube's middle targets are green-red, red-blue, blue-orange, and orange-green. Those names are examples of adjacent center pairs, not a requirement that your front always be green. Use the actual centers to name a destination and keep white down while selecting which side to face during setup.
The white center stays down and the yellow center stays up. Face names U, F, R, L, B, D mean positions. Sticker letters mean colors: Y yellow, W white, G green, R red, O orange, B blue. Each face is viewed directly from outside. Purple outlines follow the same whole piece across states, not the same grid square.
The starting position for an insertion is the top-front edge, abbreviated UF. This is one piece with a sticker on U and another on F. Turn U until the side-facing sticker is above its matching center, then regrip to make that center front. The match is a vertical pair consisting of the edge's side sticker and the center below. A same-colored corner nearby does not establish the setup. Once the edge is at UF, its upward sticker identifies the second side center and therefore the middle slot it should enter.
For the right example, the green-red edge begins with green facing front above the green center and red facing up. The red center is on the right, so the destination is the front-right middle edge slot. For the left example, green faces front and orange faces up above the same green front center. Orange belongs on the left. Both examples have a green front match, but their destinations differ. Choosing a sequence from that front sticker alone discards the second color that distinguishes the two pieces and the two required actions.
An upward red sticker does not always mean insert right. Regrip the entire teaching cube by y and red becomes the front center while blue becomes the right center. A correctly prepared edge with blue upward then belongs right. Position R means your current right face, whereas the letter R printed inside a sticker means red. B likewise means back position or blue color. Read center positions after every setup regrip instead of carrying over the original green-front arrangement in your head when the view has changed.
The white center stays down and the yellow center stays up. Face names U, F, R, L, B, D mean positions. Sticker letters mean colors: Y yellow, W white, G green, R red, O orange, B blue. Each face is viewed directly from outside. Purple outlines follow the same whole piece across states, not the same grid square.
A useful wrong-setup comparison uses the right example with one extra U turn. The green-red edge no longer sits at UF above the green center, so the right insertion's starting condition is absent. Its colors still identify the same home. Undo that setup turn or realign the top until the side sticker matches its center again. Do not choose left because the piece moved left. Insertion direction describes the destination relative to the matched front center, not the target's current location before it has been aligned.
Right insertion is U R U' R' U' F' U F. Left insertion is U' L' U L U F U' F'. Keep the grip fixed throughout either sequence. Each sequence temporarily opens the white layer, places the edge, and restores the white layer by its end.
Learn one side first, then the other. Notice that the top first moves away from the destination: U for a right insertion, U' for a left insertion. Do not stop when the white layer looks disturbed halfway through.
The right insertion is U R U' R' U' F' U F. The first U takes the selected edge away from its intended right slot. This seems backward only if you imagine directly dropping the edge downward. A face turn moves an entire layer, so the sequence must arrange a route that inserts the edge while repairing the white pieces it displaces. Read the first four moves as U R U' R', then the last four as U' F' U F. Keep the grip between chunks.
Track the green-red edge in the prepared right example. At UF it has green front and red up. After the first U it reaches the upper-left edge position with green left and red up. R does not touch that edge. U' brings it back to UF, and R' still does not touch it. The next U' takes it to the upper-right edge position with green right and red up. F' does not touch it there. The following U returns it to UF; the final F carries it into the front-right middle slot.
The white center stays down and the yellow center stays up. Face names U, F, R, L, B, D mean positions. Sticker letters mean colors: Y yellow, W white, G green, R red, O orange, B blue. Each face is viewed directly from outside. Purple outlines follow the same whole piece across states, not the same grid square.
After that last F, green faces front and red faces right, so both stickers match their centers. Notice that the selected edge itself spends much of the sequence in top positions while other pieces move to prepare its destination. Following only this edge therefore cannot explain white-layer preservation. Inspect the bottom white corners and edges as well. The insertion temporarily moves some of them, then restores them by the end of all eight moves. The guarantee belongs to the full sequence in a fixed grip, not to each chunk or every individual turn.
The left insertion is U' L' U L U F U' F'. It has the corresponding route on the other side. From UF, the green-orange target first travels to upper-right with green right and orange up. After L' and U it is back at UF; L does not touch it there. The next U sends it to upper-left with green left and orange up. F leaves it there, U' returns it to UF, and F' inserts it at front-left with green front and orange left. All directions are still read from outside their named faces.
The two sequences are related by a left-right reflection, which also reverses the quarter-turn directions. Merely replacing each R with L in the right sequence is not enough. Compare the opening U on the right with U' on the left, and the ending F with F'. The target must approach the opposite side of the same front layer. If you forget the left sequence, inspect its written moves or recall cue rather than inventing a partial mirror. An invented change can disturb the white layer.
| Part of insertion | Right destination | Left destination |
|---|---|---|
| Move away first | U | U' |
| Open side and return top | R U' R' | L' U L |
| Approach through front | U' F' U F | U F U' F' |
| Required completed effect | UF edge to front-right; white restored | UF edge to front-left; white restored |
In the demonstration, choose Insert right and pause before stepping. Compare the target's first sideways motion with the later U' that takes it toward the right. Use the net to check the front-right slot after the last F, not when the target merely returns to UF. Then select Insert left and compare the reflected route. Presets replace the initial state and restart playback; Back revisits the current example's preceding turn. Prepared examples may finish the cube; ordinary middle-layer work does not require a solved yellow face.
If no suitable nonyellow edge remains on top but the middle is unfinished, an edge is trapped in a wrong middle slot or is flipped in its own slot. Bring that bad slot to front-right. Perform the right insertion using the top edge as a temporary replacement.
The displaced edge is now on top. Reinspect its two colors, align its side sticker to a center, and choose left or right normally. Do not blindly repeat the same sequence without resetting the setup. Stop when both bottom layers match all centers.
When an edge is trapped in the middle, legal face turns can bring it to the top. An insertion replaces the piece in its destination slot. That displaced piece must go somewhere, and in this method it comes into the top layer. Use this effect deliberately at an incorrect slot, with a temporary top edge as the replacement. The replacement need not belong there because the purpose is recovery, not immediate completion of that slot. Choose an incorrect slot for this temporary replacement; leave solved edges alone.
There are two kinds of wrong middle slot. A misplaced edge has the wrong color pair for its neighboring centers. A flipped edge has the correct pair but the colors face the opposite directions. For example, red on front and green on right in the green-red slot is flipped. It is not solved merely because those two colors occur between the right centers. A legal recovery moves the entire piece through the top layer. It returns both stickers facing their centers without altering the edge by hand.
The white center stays down and the yellow center stays up. Face names U, F, R, L, B, D mean positions. Sticker letters mean colors: Y yellow, W white, G green, R red, O orange, B blue. Each face is viewed directly from outside. Purple outlines follow the same whole piece across states, not the same grid square.
Bring the bad slot to front-right with a y regrip and use the right insertion once. Keep white down and keep that grip throughout all eight moves. Yellow may enter the bad slot temporarily, but cannot remain at the final checkpoint. Track the displaced edge's colors, not a fixed top square that another piece may occupy. It may not emerge at UF. Search the top layer after the sequence, locate its side-facing sticker, and align that sticker above its matching center before selecting an insertion.
The pictured flipped green-red example makes the need for realignment concrete. After the ejection sequence, that edge sits at upper-back with red facing up and green facing back. It is no longer trapped, but it is not ready at top-front. A U2 turn brings it to UF with green front and red up. The normal right insertion then places it correctly. Repeating the right sequence immediately without that U2 would start with the target at the wrong top position. Two insertions solve this recovery only with the setup between them.
If every top edge contains yellow while the middle is unfinished, at least one of the four nonyellow middle edges is trapped below. With the white layer correct, those edges cannot be hidden among white-layer edges. This counts whole piece identities, not visible yellow stickers. Search the four middle slots for a wrong pair or a flipped pair. Eject one such edge, solve the top case it creates, and inspect again. Do not eject a solved edge simply for easier visibility in the solid view.
The white center stays down and the yellow center stays up. Face names U, F, R, L, B, D mean positions. Sticker letters mean colors: Y yellow, W white, G green, R red, O orange, B blue. Each face is viewed directly from outside. Purple outlines follow the same whole piece across states, not the same grid square.
Ejection is also useful when a nonyellow top edge exists but another desired edge is trapped. You can solve the accessible top edge first if it has a clear setup. Do not interpret the no-usable-top condition as the only legal time to recover a bad slot. It is a sign that recovery has become necessary. In either order, the completed insertion must preserve the white layer and the other solved middle slots. Inspect preserved pieces at the boundary, even if the target looked correct before move eight.
In practice, select Insert right and identify the UF edge without opening the recall cue. Name its front sticker, the matching front center, and the side center matching its upward sticker. Enter the eight moves with the face-turn buttons, waiting for each animated turn to finish. Inspect both bottom layers in the net before pressing Check my progress. The checker reads the current practice state without moving it or revealing a solution. Success confirms the two-layer pattern, not unaided recall of the setup or moves.
Repeat with Insert left, but make the recognition decision before recalling the moves. Green above the front center does not choose a side; the upward orange sticker does. After completing the sequence, look at the front-left edge's two stickers and both centers to explain the result. If the wrong sequence was selected, do not try random extra top turns to fix the middle piece directly. Undo the known mistaken moves in reverse order, or Restart this attempt for a clean prepared state. Restart replaces history and discards the half-finished insertion.
The white center stays down and the yellow center stays up. Face names U, F, R, L, B, D mean positions. Sticker letters mean colors: Y yellow, W white, G green, R red, O orange, B blue. Each face is viewed directly from outside. Purple outlines follow the same whole piece across states, not the same grid square.
For a setup comparison, restart Insert right and turn U once. Locate the green-red edge in the net and state why its two colors still name the same home. Now undo that U before inserting, or align it deliberately with top turns. The demonstration above does not follow these practice moves; its diagram remains an independent example. Do not copy a demonstration's next move unless both starting state and grip match. This separation lets you test recognition on a changed setup rather than simply reproduce whatever the current playback happens to display.
To inspect a recovery example without a new preset, begin with Insert right, finish its insertion, and then execute right insertion twice, followed by U and one more right insertion. In this constructed legal state the green-red edge is flipped in its middle home and the white layer is still correct. Use the illustrated recovery: eject with one right insertion, locate the target at upper-back, realign with U2, then insert right. This constructed route uses existing buttons; there is no flipped-edge preset or arbitrary-state solver.
For recall, separate the branch decision from the move list. Say that a top edge must contain no yellow, its side sticker must match front, and its upward sticker chooses the neighboring center. Then recall the corresponding eight moves. If you need Show a recall cue, compare which half of the selected sequence was missing, then restart and test that specific route. Knowing both lists without recognizing their setups cannot solve the stage reliably. A correct destination cannot compensate for a missing inverse mark or a changed grip.
| Current condition | What it means | Action |
|---|---|---|
| Nonyellow edge on top, front matched | Direct insertion available | Top sticker chooses left or right |
| Nonyellow edge on top, front unmatched | Setup incomplete | Align to center before inserting |
| Only yellow edges on top, middle wrong | Needed edge trapped below | Eject an incorrect middle edge |
| Both lower layers match all centers | Middle stage finished | Stop insertions; inspect yellow edges next |
Stop when every sticker in the bottom two layers matches its face center. Inspect all four side faces, including the back and left faces in the net, plus the white face below. A front-only view can hide an incorrect rear edge. Yellow stickers may still face sideways in the top layer, and top corners need not occupy their final homes. Those are later tasks. Do not run another insertion merely because the yellow top looks unfinished. This method establishes a checkpoint, not universally shortest sequences or lasting recall from prepared examples.
Prepared states isolate one task. Some examples happen to finish the whole cube; on a general scramble, stop at the stated checkpoint and continue with the next unfinished step.
The front sticker matches F; the top sticker matches R.
Next: U. top face: clockwise quarter turn, viewed directly from outside that face. Completed 0 of 8 moves.
URU'R'U'F'UF
Sticker letters are colors: W white, Y yellow, G green, B blue, R red, O orange. Face names are positions: U top, D bottom, F front, B back, R right, L left. Read B and R in context.
The net shows the last completed turn; the solid view shows the turn in progress. Presets replace the starting state and reset playback. Reset keeps the selected example. Do not copy an autoplay demonstration onto your cube unless your starting state and grip match. Use manual steps for following along.
Start from a prepared state. These controls change this practice cube only. They do not control the demonstration above or your physical cube. Goal: Finish the bottom two layers.
0 moves in this attempt. Limit 500; undo or restart if reached.
Right: U R U' R' U' F' U F. Left: U' L' U L U F U' F'.
A cue is help, not a failure. After using it, restart the prepared state and attempt the same task without reopening it.
Sticker letters are colors: W white, Y yellow, G green, B blue, R red, O orange. Face names are positions: U top, D bottom, F front, B back, R right, L left. Read B and R in context.
Face turns and whole-cube regrips animate in the solid view; the net updates when the turn finishes. Reduced motion shows the result immediately. Wait for a turn to finish before starting another. Undo can cancel the current turn. A new preset or Restart cancels motion, replaces the entire attempt and clears its history. Undo reverses only the last practice turn. Check does not move pieces or reveal an automatic solution. State is local to this page and is not saved after reload.
The top-front edge has green facing front above the green center, and orange facing up. Orange is the left center. Which insertion applies?
The front match is already correct; inspect the destination color.
Use the left insertion. Orange belongs beside the orange center on the left. The initial U' moves the edge away so the sequence can insert it and restore the white layer.
Can you fix a flipped middle edge by twisting it directly with your fingers?
Use legal layer turns to return it to a known case.
No. Bring the slot to front-right and insert a temporary top edge to eject it. Then align the displaced edge on top and choose the appropriate insertion. The whole piece must move through legal turns.
The explanations, simulator, and diagrams are original. These references support standard notation and beginner procedures. The course keeps white down, including the final twisting stage. Do not mix its final sequence with a tutorial that flips the cube over.
These examples use states produced by legal turns. The simulator has no sticker-painting input and does not diagnose physically twisted, reassembled, or damaged cubes. Successful model checks do not establish physical-device usability or long-term recall.