Jacob Keener Solves 3D-Printed 27x27 – The Largest Cube Ever Fully Solved
Jacob Keener has achieved an extraordinary milestone in the world of twisty puzzles, successfully solving his custom-built 27x27x27 Rubik's Cube, making it the largest physical cube known to have ever been fully solved.
Unlike the mass-produced puzzles available from manufacturers such as MoYu and DianSheng, Keener's enormous 27x27 was designed and 3D printed by Keener himself.
The achievement represents not only an impressive feat of puzzle solving, but also an enormous amount of work designing, manufacturing and assembling a functional twisty puzzle with thousands of individual pieces.
How Big Is a 27x27 Cube?
A standard Rubik's Cube has three layers along each axis, giving it six faces with nine stickers or coloured squares on each face.
A 27x27, by comparison, has 729 visible squares per face, or 4,374 across all six faces.
The cube contains more than 4,000 individual components, all of which had to be manufactured and assembled into a mechanism capable of turning.
According to its listing on the TwistyPuzzles Museum, Keener's cube was designed in Fusion 360 and printed using PLA filament.
Despite having 27 layers along each axis, the finished puzzle weighs approximately 1.7 kilograms.
Creating a working puzzle of this size presents significant engineering challenges. Each layer must be able to turn while the thousands of individual pieces remain securely connected to the internal mechanism.
And, of course, building the puzzle is only half the challenge. Keener has now demonstrated that it can actually be scrambled and solved.
Watch Jacob Keener Solve the 27x27
Keener documented the achievement in a video on his YouTube channel, showing the remarkable puzzle and the process of solving it.
Watch Jacob Keener's 27x27 Solve on YouTube
The video is particularly interesting because a puzzle of this size is completely different from the cubes most speedcubers are accustomed to solving.
Even relatively simple tasks such as locating pieces, aligning layers and executing algorithms become much more challenging when working with 27 layers.
How Does It Compare to the 21x21 and 23x23?
For several years, the largest widely available NxNxN cube has been the MoYu 21x21, which has 2,402 visible pieces.
Keener's 27x27 is a considerable step beyond that, with 4,374 visible squares.
He had also previously constructed and solved a 23x23, which contains 2,906 visible squares.
The progression illustrates just how quickly the boundaries of large twisty puzzles have been expanding.
| Puzzle | Visible squares |
|---|---|
| 17x17 | 1,734 |
| 19x19 | 2,166 |
| 21x21 | 2,646 |
| 23x23 | 3,174 |
| 27x27 | 4,374 |
These figures count visible facelets, including the fixed centre on each face, rather than individual moving pieces.
Although even larger cubes have been constructed, creating a puzzle and demonstrating that it can be fully solved are two very different achievements.
That is what makes Keener's latest accomplishment particularly significant.
The Challenge of Solving a 27x27
Despite its enormous size, a 27x27 can theoretically be solved using the same general reduction method familiar to anyone who has solved a 5x5, 7x7 or larger cube.
The basic stages are:
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Solve the centres: Build six enormous 25x25 centre sections.
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Pair the edges: Match the corresponding wing pieces to form 12 complete edges.
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Solve like a 3x3: Once reduced, finish the remaining puzzle using standard 3x3 techniques, accounting for any parity cases.
However, the number of pieces makes each stage vastly more demanding.
A single centre on a 27x27 contains 625 facelets, compared with just 25 on a 7x7.
The edge-pairing stage is similarly enormous, with 25 pieces making up each complete edge.
The challenge is therefore less about learning completely new algorithms and more about managing the huge number of pieces, maintaining concentration and carefully handling a complex custom-built mechanism.
The Future of Giant Rubik's Cubes
Keener's achievement raises an interesting question: how much bigger can functional twisty puzzles become?
The largest cubes that have been physically constructed are already considerably bigger than 27x27, but their enormous complexity makes them difficult to manipulate, let alone solve completely.
Advances in 3D printing and puzzle design have made it possible for individual enthusiasts to create puzzles that would once have been almost impossible to manufacture.
Keener's 27x27 is an excellent demonstration of what can be achieved by combining engineering expertise with a passion for twisty puzzles.
It also highlights the distinction between the largest puzzle ever constructed and the largest puzzle ever successfully solved.
For now, Jacob Keener's 27x27 stands as the largest physical NxNxN cube known to have been fully solved, setting a remarkable new benchmark for the giant-cube community.
Could a fully solved 29x29, 31x31 or even larger cube be next?
