Monday, 5 September 2011

Cast Duet

I quite like the Cast Duet. I find it very refreshing because here at last is a puzzle which has:-

1. No secret locking mechanism
2. No hidden maze
3. No ball bearings rolling about which can be heard but cannot be seen
4. No internal magnets
5. No centrifugal force applicable
6. No tapping (or banging) of the puzzle
7. No dexterity of hand movement required
8. No other seemingly impossible this or that

Click to enlarge the photo to see the notches  which are cut into the grid
You look at the Duet and it stares back at you, fully exposed for what it aluminium grid with 9 squares and a number of notches cut into the grid. Attached to one corner of the grid a pair of detachable rings joined together by magnets. The grid measures about 2 3/8in square and the rings are about 1 1/4in in diameter. Quality of construction is good.
The object of the puzzle is to remove both the rings from the grid. To do this one must first separate the two rings (easily done) and navigate each ring out of the grid. The notches on the grid serve as "paths" to aid the passage of the rings from one square of the grid to the next, without which it would be impossible for the rings to move at all. Each of the rings have to be rotated and/or flipped over to achieve movement.

I didn't have to take very long to remove the rings since I could see exactly what I was doing. Apart from merely removing the rings, Hanayama has added extra levels to make the puzzle more challenging (eg; to get the rings to the centre of the square). I didn't bother with this since I was quite happy to have gotten the rings out of the grid. This puzzle is rated 5. However, I think its more towards 4 for just getting the rings out.


  1. In analyzing the puzzle I found it useful to create a map showing the position of one ring, including orientation. Using my complete map of the puzzle, it is then easy to solve to any position. See my writeup at

  2. George, thanks for the write up on Duet and other puzzles....very useful info indeed...hmm must check out the Cast Disk...