Khun Phaen (Klotski) Puzzle

This is my take on the classic Khun-Phaen puzzle. I built it with standard wood sizes so you should be able to find the materials at your local big box store. In addition, I've included STP and STL files (last step) for those that would like to print the puzzle. If building or printing doesn't suit your needs, you can purchase the same puzzle from online.

Puzzle Background: Khun Phaen was a leader in the Thia Legend. He wants to escape but is surrounded by 9 sentries.

Objective: Free Khun Phaen (large square)

Rules: Move the pieces without raising them off the board

Note that there are multiple names and variations for this puzzle. For more information, see here.

Below is the puzzle in action.

Below is an animated solution for one case.

Tools:

• Table or Miter Saw
• Band Saw (Optional)
• Drill Press
• Forstner Bit - 1" Diameter
• Forstner Bit - 3/4" Diameter
• Drill Bit - 1/2" Diameter
• Ruler
• Pencil
• Wood Clamps
• Sander
• Small Paint Brush

Materials:

• Wood - 5.5" x 24" x 0.25" Thick
• Wood - 5.5" x 12" x 0.375" Thick
• Wood - 2" x 12" x 0.5" Thick
• Wood Glue
• Paint (3 colors)
• Stain

You will be building to this drawing. All parts are color coded for easy reference. The last picture is a rendered image from CAD.

The base houses the blocks and has a slot in the front that is sized to allow Khan Phaen to escape. The last picture shows detailed dimensions for those that are curious about fit.

This thickness is arbitrary. I decided to use 3/8 (.375") thick wood to give the puzzle slightly more weight. Note that all other pieces on the base and lid use 1/4" thick wood. Use a Table or Miter saw to make this piece.

These pieces are straight forward. Cut to the sizes shown. Make 2 sides (yellow) and 1 back (cyan).

There are a few ways to make this part. I used a band saw to cut the notch. You could also cut individual pieces and glue it together.

Glue the sides to the base as shown. Use wood clamps for a better joint.

The lid is designed to stay with the puzzle when in use. Reverse the direction when storing the puzzle. I set the nominal gap between the lid and cover at 1/32 of an inch.

Same cut process as the Base Bottom

The Back (orange) cut is straightforward. The sides have semi-circle cutouts. These allow you to pull the base from the lid. The green drawing shows the final dimensions. However, I started with the gray drawing and cut the part in half. I used a 1" Forstner bit for the hole and drilled from both sides to prevent break out.

This part is similar to the Base Front except that I used a strip (pink) along the top. Again, you could build it up with pieces or notch using a band saw or chisel.

As with the Base, glue sides to the Top.

Sand the base and lid. I had a few small gaps that I filled with wood filler (glue and saw dust). I finished the parts with black cherry stain and two coats of polyurethane. In retrospect, I feel I should have used a lighter stain for the blocks - too late now.

The nine sentries are made from 1/2" thick wood. I uses scrap hardwood (type unknown). Note that Khun Phaen is made from 3/8" thick wood. His svelte thickness allows him to escape through the passage. Note that the slot in the puzzle is shown as 3/8" thick. You might need to sand 1/32 of an inch off Khan to guarantee passage.

For the holes, I used the same process from my Instant Insanity puzzle. I used a 3/4" diameter Forstner bit to recess the pockets. I didn't like the small hole from the center of the bit so I went back and used a 1/2" drill to enlarge the center section of the hole.

Cool slow motion of the Forstner Bit in use.

The hole colors are up to you. I used what was available from my daughter's craft paint.

Add the pieces to the base. If you built everything correctly, there should be a 1/8" gap on the top and right side when all the blocks are pushed to the lower left corner.

There are multiple starting options. This starting position is shown in the solution video in the first step.

These fit together nicely.

I feel it turned out pretty nice. Like I said mentioned earlier, I think a lighter stain or just a finishing oil would have been better choice for the hardwood blocks.

Smaller (purchased version) size comparison.

I've included STP and STL files for those with access to a 3D printer. No assembly is required for the Base and Lid. However, you will still need to paint the holes on the game pieces.

Thanks for viewing!