Gordian's Knot: What You Are Actually Holding

Quick answer: the puzzle sold as Gordian's Knot is Extreme Torture, designed by Frans de Vreugd around 2002. It is a six-piece separated board burr, and although almost every source gives its level as 28.21.9.8.3 for 69 moves, de Vreugd's own published research gives 28-22-9-8-3, which is 70.

Best for: anyone who bought it in a toy shop and has since discovered it is not a toy.

Most puzzles sold in blister packs are designed to be solved. This one was designed to be the hardest thing a computer search could find, and then it ended up in blister packs anyway.

What Is Gordian's Knot?

Six interlocking pieces that come apart in one long forced sequence and go back together in the reverse of it. No rotation, no force, no trick: every move is a straight slide in one of six directions, which is what makes it a burr rather than something looser.

More precisely it is a board burr. The pieces are flat plates rather than square-section sticks, notched on both faces, and they interlock in three perpendicular directions. That distinction matters because board burrs can reach move counts that stick burrs cannot, which is the entire reason this puzzle exists.

ThinkFun mass-produced it in plastic with a solution booklet. The first commercial run was made in acrylic by George Miller.

Who Actually Designed It?

Frans de Vreugd, a Dutch designer, around 2002, under the name Extreme Torture. We have a full profile of him and the work.

He did not find it by hand. He worked with Dic Sonneveld and Goh Pit Khiam on Burrgrower, a program written specifically to raise the level of a puzzle: Sonneveld wrote the first version and Goh rewrote it in C++. Extreme Torture is what that search produced when pointed at separated board burrs.

The name on the box is therefore marketing, and the name the puzzle community uses is the designer's own. Both refer to the same object.

How Many Moves Does Gordian's Knot Really Take?

Seventy, and nearly every source says sixty-nine.

The figure repeated across retailers, forums and collection databases is level 28.21.9.8.3, which sums to 69. De Vreugd's own paper Separated Board Burrs, published in the puzzle journal CFF, gives the level as 28-22-9-8-3. That sums to 70.

The difference is the second number, 21 against 22, and the designer's own published research is the better authority than a figure copied between product listings. We corrected our own product pages to 70 when that paper came to light, having previously carried 69 like everyone else.

What the notation means is worth unpacking, because it is where the difficulty lives. The first number is the moves needed to remove the first piece: 28 of them, before anything at all comes free. The rest describe each subsequent piece. A standard six-piece burr usually frees its first piece in under ten.

Why Is It So Hard?

Because nothing along the way looks like progress, and there is no feedback until the end.

Twenty-eight moves with no piece released means twenty-eight opportunities to conclude you have gone wrong. Boards slide, the shape changes, and nothing separates. There is no partial success to confirm you are on the right line, and a single wrong turn early leaves you shuffling in a region from which the solution is unreachable.

De Vreugd's own observation about the design is the useful one: the internal geometry is arranged so that nothing is wasted. Seven moves can be required to shift a single board three units. Every one of those seven is necessary, and none of them feels necessary.

This is the same property described in level notation explained, pushed as far as a computer could push it.

How Do You Solve Gordian's Knot?

Honestly: most people do not, and the boxed version includes a booklet for exactly that reason.

We will not publish a move list, partly because a 70-move sequence is useless to read and partly because the retail version already ships with one. What is worth knowing is how to approach it.

Do not hunt for a piece to remove. For the first twenty-eight moves there is none. Treating it as take-apart from move one is the commonest mistake and guarantees frustration.

Work out which board can move at all, and in which direction. At most points very few moves are legal. The puzzle is far more constrained than it looks, and listing the legal moves is more productive than trying them.

Record your sequence. Without notes you cannot reverse out of a dead end, and with a 28-move opening you will need to. This is the single most useful habit for puzzles at this level.

Reassembly is the harder half. Taking it apart in a shop with a booklet is one thing. Our version ships as six loose boards and nothing else, which is a materially different puzzle.

Gordian's Knot or Extreme Torture: Which Should You Buy?

They are the same design and a different experience.

The ThinkFun version is moulded plastic, arrives assembled and includes the solution. It is the forgiving way to meet the puzzle, and there is nothing wrong with it.

Our Extreme Torture arrives as six loose boards with no booklet. Nothing to take apart, nothing to consult, and the 70-move assembly in front of you. We are straightforward that most people will not solve it unaided, which is the point of carrying it rather than a caveat.

If that sounds like too much, the sensible entry to the designer is his other work in mechanical puzzles, and the interlocking guide explains where board burrs sit among the rest.

Frequently Asked Questions

What is the Gordian's Knot puzzle?

A six-piece separated board burr designed by Frans de Vreugd around 2002 as Extreme Torture, mass-produced in plastic by ThinkFun as Gordian's Knot. The pieces interlock in three directions and come apart in one long forced sequence of straight slides.

How many moves does Gordian's Knot take?

70. Most sources give level 28.21.9.8.3, which is 69, but de Vreugd's own paper Separated Board Burrs in the journal CFF gives 28-22-9-8-3, totalling 70. The first 28 moves release nothing at all.

Who invented Gordian's Knot?

Frans de Vreugd, a Dutch designer, around 2002. He found it using Burrgrower, a program for raising a puzzle's level that Dic Sonneveld first wrote and Goh Pit Khiam rewrote in C++. The first commercial run was made in acrylic by George Miller.

Is Gordian's Knot the same as Extreme Torture?

Yes, the same design under two names. Extreme Torture is what the designer called it; Gordian's Knot is the name ThinkFun sold it under.

Why is Gordian's Knot so difficult?

Because no piece comes free for 28 moves, so there is no feedback that you are on the right line, and one wrong early move can leave you in a region the solution cannot be reached from. The geometry is arranged so nothing is wasted and nothing looks like progress.

Can you solve Gordian's Knot without the instructions?

Very few people do. The retail version ships with a solution booklet precisely because the 70-move sequence is beyond unaided trial and error for almost everyone. Reassembly from loose pieces is harder again than disassembly.