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Devil's knot solver (6-piece burr puzzle)

Six wooden sticks that won't go back together? Describe your devil's knot below and Emboîto finds the solution to your 6-piece burr puzzle, then shows the assembly in 3D, step by step. The solution is also available as a printable PDF.

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Enter each piece

  1. Number your pieces from 1 to 6 in pencil.
  2. Lay the piece flat in front of you, with the two ends to the left and right.
  3. The middle of the piece is cut into small squares, each half a width. Tap a square to show whether wood is missing on top, underneath or all the way through.
  4. Turn the 3D drawing with your finger or mouse and check that it looks like your real piece.
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The middle of the piecetop view
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Solve

How to describe your puzzle

A devil's knot is made of six wooden sticks with a square cross-section. In the middle of each stick, small blocks of wood have been cut away, and those notches are what let the sticks lock together. Emboîto needs to know where the notches are, piece by piece.

Start by numbering your pieces from 1 to 6 with a pencil, in any order you like. Lay the first one flat in front of you, with its two ends to the left and right. The middle of the piece is divided into small squares, each half as wide as the stick, and the site draws them as a grid. Tap a square to say whether wood is missing on top, underneath, or all the way through. Each tap moves to the next state: solid, notched on top, cut through, notched underneath, then solid again.

The 3D drawing changes with every tap. Turn it with your finger or mouse and compare it with your real piece before moving on to the next one. If your sticks are 3 or 5 times as long as they are wide rather than 4, change the length under “Options”. Your entries are saved on your device as you go, so you can close the page and come back later.

How Emboîto finds the solution

When all six pieces are entered, tap “Find the solution”. Solving runs in your browser, on your phone or your computer, and your pieces aren't sent anywhere.

Emboîto first looks for the ways the six pieces can cross to form the knot, trying the possible positions of each one. For every arrangement it finds, it then checks whether the knot can really be taken apart, piece by piece or in blocks. It keeps the first arrangement that comes apart and works out the assembly order from it.

Solving can take up to a minute, and the page stays usable in the meantime. If your pieces can't form the cross, or if no assembly order works, the site tells you so. One square has probably been entered wrongly.

The result appears as written steps with a 3D animation that you follow at your own pace. A button also prepares a PDF in which every piece and every step is shown as a picture, ready to print.

History and variants

The devil's knot goes by several names: the carpenter's cross, the Chinese knot or the 6-piece burr. It's a traditional shape, and nobody knows who made it first.

It consists of six sticks with a square cross-section, which cross to form a three-dimensional cross. Depending on the model, the pieces are 3, 4 or 5 times as long as they are wide. Emboîto offers all three lengths, starting from 4 times the width, and you pick one under “Options”.

The site handles the six-piece version. A burr with more or fewer pieces isn't supported. The notches, on the other hand, are up to you: on top, underneath or all the way through, exactly as your model was cut. If your devil's knot is homemade, enter it as it is, without trying to correct it.

Frequently asked questions

Is the devil's knot the same as the carpenter's cross?

Yes, they are two names for the same puzzle, which is also called the Chinese knot or the 6-piece burr. Emboîto treats them all the same way: six sticks to enter, then an assembly to follow.

How do I find the solution to my 6-piece burr puzzle?

Enter each piece in the grid, checking it against the 3D drawing, then tap “Find the solution”. The site shows the assembly step by step. You can also tap “Sort in assembly order” to renumber your pieces in the order they go in.

Why is there no solution for my devil's knot puzzle?

One square has probably been entered wrongly on one of the pieces. Go through them one by one, comparing the 3D drawing with the real piece, and check the length chosen under “Options”.

Can I get a printable solution?

Yes. Once the solution is found, the “Download the solution (PDF)” button prepares an A4 document with every piece, then every step as a before and after picture. Number your pieces as shown on the PDF before you begin.

Are my pieces sent anywhere?

No. Solving runs in your browser and your saved puzzles stay on your device. The share link carries your entry after the # sign, a part of the address that the browser never sends to the server.

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