Introduction: Japanese Ring Puzzle
The Japanese Ring Puzzle first intrigued me years ago when I saw a video of a man that had been searching for the solution for ten years. It was interesting to see his thought process and quest to find the solution to a seemingly impossible puzzle.
The goal of the puzzle is to move the ring from the green side to the read.
Through all my research I was unable to locate the origin of this puzzle, but I decided I could make a higher quality puzzle than what is currently available for purchase.
Upon completion, this is definitely one of my favorite puzzles I've ever made.
Step 1: Tools and Materials
Step 2: Turn Top of Puzzle
On the lathe, turn a cylinder with an exterior diameter of 1 3/4 in. Use a 1 in. forstner bit to create the interior diameter. Sand the ring smooth.
Part off the ring at a width of 3/4 in. and sand the rest of the ring smooth.
Step 3: Drill Holes
Using a 3 1/2 x 6 in. of hardwood, drill a 3/8 in. through hole in the center of the board.
Drill a corresponding hole in the bottom of the wood ring. Be careful not to punch through the other side.
Using a 5/8 in. forstner bit, drill a recess 1/2 in. deep on the bottom of the hardwood board. This will be where the knots in the rope go. Drill a 1/4 in. hole through the rest of the board on each side.
Step 4: Shine Rod
Insert the 3/8 in. rod in your drill. Starting with 80 grit sandpaper, shine and polish the rod in increasing grit until 600 grit is reached. From there, use polishing compound to really make it shine. Cut the rod to a length of 4 1/2 in.
Using a hacksaw, cut horizontal grooves in each end of the rod. This will give the epoxy extra surface area to securely attach it.
Step 5: Apply Finish
Apply 3-4 coats of lacquer (or your desired finish) sanding with 600 grit sandpaper or fine steel wool between coats.
Step 6: Assemble
Mix the two part epoxy and apply in the holes with a small stick or rod. Be sure that the ring on top is parallel with the front and back of the bottom board.
Step 7: Drill Hole Through Marbles
Clamp a scrap piece of wood to the drill press table. Drill a nesting hole to hold the marble using a 1 in. forstner bit. Replace the bit with a 8 mm diamond hole saw. Holding the marble with a pair of gloves, slowly grind a hole through the marble. Be sure to continually cool and clean out the hole with fresh water.
Be careful as you approach the other side of the marble as applying too much force can cause the back to blow out. Some blow out was unavoidable but that face will be down against the board in the final puzzle.
Step 8: Assemble Puzzle
To assemble, tie a knot in one end of the rope. Pass it through the bottom board, first marble, then ring. From there, follow the pattern shown above, then pass it through the second marble followed by the other side of the board.
To define the final length of rope, take a look at the next step for directions on how to solve the puzzle. You want the rope short enough that the ring can just pass through the 'switching move' to solve the puzzle.
Step 9: Solve the Puzzle
Solve the puzzle by:
- Pulling the loop of rope over top of the wooden ring
- Pull each rope coming from the marbles to the top of the wooden ring
- Slide the metal ring to the top of the wooden ring
- Pull tight the two ropes from the marbles
- Push the middle loop through the middle of the wooden ring
- Slide the metal ring through the loop created in the rope (when sizing the rope in the previous step, this is the 'switching move' where it should be tightest)
- Lift the metal ring to the top of the wooden ring once more (now on the opposite side of puzzle)
- Push the loop back through the wooden ring
- Pull the loop loose and slide the metal ring to the marble
- Pull the loop back over the top of the wooden ring to return to the unsolved position