Osanori Yamamoto and the Apparent Cube

Osanori Yamamoto builds cubes that are not there.

Look into one of his frames when it is solved and you see a cube - flat faces, square edges, a solid block sitting in a cage. Take it apart and you find two or three small pieces and a great deal of empty air. The cube was never solid. It only ever had to look solid from the outside, and that is the whole design. The form has a name: an apparent cube, sometimes called a transparent cube.

Which inverts the rule every other packing puzzle taught you. You are not filling a volume, where every gap is a failure. You are filling the openings - and what sits behind them is not the test.

He is the best in the world at this. Here is what that looks like.

Who Is Osanori Yamamoto?

A Japanese designer, working at it full time, with hundreds of puzzles behind him.

What marks him out is thoroughness. He does not produce one clever idea and move on - he takes a single concept and works it through a long series of designs, exhausting what it can do before starting the next one. That is why his catalogue reads as families rather than one-offs, and it is why other designers so often take his ideas as a starting point. A great many modern packing puzzles are, one way or another, downstream of something Osanori did first.

His two best-known series are 2D packing puzzles and transparent cubes. We carry 13 of his designs, which is the deepest single holding in the shop.

How an Apparent Cube Works

Look at the photo above. The white part is not a box, it is a cage - large openings on every face, almost nothing solid.

That is deliberate, and it is the opposite of what other designers do with a container. Volker Latussek closes the box almost completely so you cannot see in. Frederic Boucher cuts deliberate windows into a solid box. Yamamoto removes most of the box altogether and then asks you to rebuild its faces out of pieces.

So the goal is not a solid block. It is that every opening in the frame reads as filled when you look at it. Behind those faces the packing can be full of holes, and on his harder designs it usually is - the interior is a lattice with a great deal of nothing in it.

Two things follow, and they are why the form is so hard.

You cannot reason by volume. On an ordinary packing puzzle you can count: this much space, these pieces, therefore this arrangement. Here the pieces do not have to account for the whole interior, so that arithmetic tells you nothing.

Nothing is hidden, and it does not help. You can see every piece through the frame the entire time. Most puzzles get their difficulty from concealment; this one hands you full information and is still Hard.

One case worth understanding properly: Toplun is an apparent cube where the arithmetic happens to come out exact. Its six pieces total precisely 27 voxels, which is a full 3x3x3 - so when the openings are filled, there is nothing left over and nothing missing. It is the same form, solved the same way. The solid result is a consequence of the piece count, not a different rule.

The Other Series: 2D Packing

His other well-known body of work is flat: pieces into a tray, one layer, no stacking, and the same instinct behind it - very few pieces, an awkward boundary, and far fewer valid arrangements than the shapes suggest.

We do not carry his 2D designs and have no plans to, so this is context rather than a recommendation. It is worth knowing about because it shows the same mind working in two dimensions instead of three.

Why So Few Pieces Still Beats You

The arithmetic here is genuinely surprising, and Kevin at PuzzleMad put a number on it. After solving Aris 3 - a three-piece Yamamoto design we do not carry - he modelled it in BurrTools to see what he had actually been up against.

Those three pieces can be arranged into 65 different 3x3x3 shapes. Plenty of room, you would think. But the opening demands a 2x2x1 face at the top and another diagonally opposite it at the bottom, and once that is enforced the number of assemblies you can actually build drops to 14.

That is the whole trick in one number. The pieces are not doing the work - the opening is. Yamamoto designs the frame first and lets it eliminate almost every solution the pieces would otherwise allow.

Allard Walker hit the same wall from the other direction with Shutout, which we do carry. Its six pieces are all the same plain shape - no weirdly shaped pieces that need to dance around one another, just six T's. It still beat him. Getting most of the pieces in is simple, he wrote, getting them all in turns out to be impossible - until the one intermediate position turns up. If a tray of six identical T shapes looks easy, his advice is to remember who designed it.

It also explains why piece count is such a poor guide to his puzzles. Level notation is the honest measure, and his two-piece designs regularly outrank six-piece ones.

The Rotation

Nearly every Yamamoto design needs at least one piece to turn rather than slide. The product pages say rotations required for a reason - it is not a footnote, it is the move you are looking for.

Kevin's phrase for it, from that same solve, is that the pieces pirouette around each other - which is about right. You are not pushing things into a hole. You are finding the one attitude at which a shape passes an opening it very obviously should not fit through.

Identical Twins makes the point as economically as possible: two pieces, and they are the same piece twice. There is no special piece to identify and no order to discover. All the difficulty is in orientation. It won a puzzlers' award at IPP37 and the Mechanical Puzzle Discord rates it among his top three.

Lucida, with the same two-piece structure, is the one that community voted number one.

Where to Start

First one: Loach Bed. It is the only Easy design we carry of his, and it teaches how a restricted opening behaves without punishing you.

Second: Waltz or Identical Twins, both Medium, both two pieces plus a frame.

Then: Lucida and Petit Ring at Hard.

The deep end: 6N, A6L and Shutout, all Expert.

If you already know you are going to want several, the Osanori Essentials set of six is the sensible way in, and the full collection of 11 exists for people who have decided. Everything sits in the Osanori Yamamoto collection.

Frequently Asked Questions

Why I Carry His Work

Osanori is my favourite apparent cube designer, and I am proud to carry his designs.

There is something else worth saying plainly. He is one of the very few people anywhere who designs puzzles for a living - not as a sideline to a job, but as the job. That is a precarious way to make a living in a small field, and it only works if people buy the puzzles.

So buying one of these is not only getting a good puzzle. It supports a craftsman working full time at something almost nobody does full time, and it directly funds the next series he makes. The range grows because people bought the last one.

Where to Go Next

His work sits inside the wider 3D packing puzzles range, and the packing puzzle guide covers how the family works.

For designers working the same problem differently, see Dr. Volker Latussek and Frederic Boucher, or browse the full mechanical puzzles catalogue.