Den 3

Den 3

Den 3 is a great packing puzzle from Osanori Yamamoto.

The goal of this puzzle is to place the 3 pieces into the 3x3x3 body, so that all openings are covered and it appears as if there is a 3x3x3 cube inside. 

What makes this puzzle great?

This puzzle is great because it has a small number of pieces (3) and a high number of moves required to place them into the body. It has a level of 19.4.3 which means it takes 19 moves to place the last piece (or to remove the first piece once they are properly placed inside). However, with only 3 pieces, there is not so many possible combinations of cubes that it requires unusually long sessions to test them all.

Configurations

You can make this puzzle in 3 configurations of difficulty:

1. Hard: Glue the top on and try to  move the 3 pieces into the body

2. Medium: Leave the top unglued, so you can put it on and off. Assemble the pieces outside the box and test configurations by placing them inside after lightly placing on the top.

3. Easy: View the piece configuration photos in the ZIP file below. Assemble the pieces and then place inside the body. Place or glue on the top and then learn how to remove the pieces from the puzzle. Once this is mastered, place the pieces inside the body.

Printing

You can print everything with PLA (see notes for pieces). I used 2 walls and 15% infill. 

For the pieces, you may wish to use 3 perimeters and 40% infill to give them some weight, which can make them slide easier. One of the pieces has 2 parts. Simply add a small amount of glue to the peg and insert into its counterpart. (the glue might be unnecessary if the fit is snug)

3D Printed pieces that need to slide over each other do not work as well as pieces made from smooth wood. The layer lines can act as "velcro" and add significant friction. I find that using a glossy filament, such as PETG works best. Some types of PLA work better than others. I find matte PLA is the worse. If using PLA, you may wish to sand/file the layer lines somewhat to reduce the sliding friction. Sand in a ventilated area where you can easily clean the dust. Since sanding tends to turn plastic white, that might be your best color choice for the pieces.

Copyright

Yamamoto holds all copyright and as such you can only use this for your own personal enjoyment.