How to Solve the Key and Keyway Cube
How to Solve the Key and Keyway Cube
The Key and Keyway Cube is eight small cubes. Some faces have a screw sticking out, some have a keyhole-shaped slot cut into them. Push a screw into a keyhole, slide, and the two cubes lock together.
That part takes about two seconds to understand. The puzzle is working out which of the many possible pairings is the one that lets all eight close into a 2x2x2 cube with every key engaged and hidden.
Watch It Solved
Puzzle Guy printed a copy and solved it on camera, including the long stretch in the middle where nothing works. Worth watching for the last few minutes especially.
What Is the Key and Keyway Cube?
It is the first puzzle designed by John Kelly, and it arrived in 2021 with no reputation attached to it at all. He was trading as Logic Puzzles then and works as Circle and Dot now, which is a neat marker of how long ago this was: the puzzle predates the company most people know him by.
Greg wrote the first review it ever got, after John sent him a copy. The verdict then was that it is a hybrid - part assembly puzzle, part interlocking puzzle - and that the solve is "a journey" rather than a single trick. It took him about an hour.
How the Joint Works
Look closely at the pieces and the mechanism is completely visible, which is unusual for an interlocking puzzle.
Each small cube carries some combination of two features. A key is a screw whose head stands proud of the face. A keyway is a slot shaped like a keyhole - a round opening at one end, a narrow channel running off it.
To join two cubes you drop a screw head through the round opening, then slide so the shank travels down the narrow channel. The head is now behind the face and cannot come back out except by reversing that exact slide. Nothing is forced, nothing is screwed in or out, and there is a satisfying click when it seats.
The One Rule That Makes It Hard
No rotations. Every move is a straight slide along an axis.
This is the whole difficulty, and it is worth appreciating how much work that single restriction does. If you were allowed to twist a piece into place, most of the dead ends would disappear - Puzzle Guy says as much on camera, that with rotations he could probably have finished in five minutes.
It is also the exact opposite of a turning interlocking cube, where a rotation is the move you are hunting for. Here, if a piece only goes in when you twist it, you have the wrong piece.
How to Solve It: Step by Step
Step 1 - sort by screw count. Lay all eight out and count the screws on each. You will find four cubes with two screws and four with one. That split is the single most useful piece of information available before you start, and most people never notice it.
Step 2 - find the pairs that actually fit. Take one of the two-screw cubes and try it against the others. Most combinations will not go at all: the screw and the keyway are in the wrong places relative to each other. Only a few pairings are even legal, which is good news - the space is much smaller than eight pieces suggests.
Step 3 - build one half. Work up to four cubes joined into a 2x2x1 slab. This part comes together with patience and is genuinely satisfying.
Step 4 - build the other half, and expect it to be wrong. This is where almost everyone stalls. You will have two halves that each look correct and will not combine. That usually means the halves are right but mirrored - the same four cubes need redistributing between them.
Step 5 - the move people miss. The final join is not a push. Bring the halves together and then slide the bottom pair downward to seat the last keys. It is a small move in a direction nobody tries, because every instinct says to press the two halves together rather than shear them past each other.
Step 6 - take it apart again. If you are solving from assembled, the disassembly is the same sequence backwards, and the first move is that same bottom slide. Photograph the cube before you start.
Tips for Getting Unstuck
Never force it. Every correct move here is light, and the click tells you when a key has seated. If you are pushing hard, the piece is wrong.
Count screws before anything else. Four and four. Groups of two-screw pieces behave differently from one-screw pieces, and mixing them up at random wastes an hour.
If two halves will not meet, do not force a third arrangement. Take one half apart and swap a piece with the other. The problem is almost always distribution, not orientation.
Stop trying to rotate. It is the instinct this puzzle is built to punish.
It ships with a small stand, which is worth using - assembled, it looks like an object rather than a puzzle.
Frequently Asked Questions
How does the Key and Keyway Cube work?
Each of the eight small cubes has screws standing proud of some faces and keyhole-shaped slots cut into others. A screw head drops through the round part of a keyhole and then slides along the narrow channel, trapping the head behind the face. All eight lock together into a 2x2x2 cube.
Can you rotate the pieces?
No. Every move is a straight slide. That restriction is the entire difficulty - with rotations allowed, most solvers would finish in a few minutes.
How hard is the Key and Keyway Cube?
Medium. Most people take between thirty minutes and a couple of hours on the first solve. It is not a puzzle that defeats people permanently, but it rarely falls quickly either.
Who designed it?
John Kelly, as his first puzzle design, released in 2021 under his earlier company name Logic Puzzles. He now designs as Circle and Dot.
Why won't my two halves go together?
Almost always because the eight cubes are distributed wrongly between the halves rather than oriented wrongly. Swap a piece between them rather than trying to force a new angle. And check you are not missing the downward slide on the bottom pair.
Is it a good first interlocking puzzle?
It is a good second one. The mechanism is visible, which makes it far less intimidating than a burr, but the no-rotation rule means it will still take you a while. Try the 6-Piece Cross first if you have never solved one.
Want More Puzzles Like This?
If the visible-mechanism aspect appealed, the wider interlocking puzzles collection is the place to go next, and the complete guide to interlocking puzzles explains how the family divides up.
For the opposite experience - where finding the rotation is the solve - try a turning interlocking cube. Everything sits inside the full mechanical puzzles catalogue.