As simple as this puzzle may seem to be to the average puzzler, there is a noteworthy train of thought to consider: all three elements (horseshoes, ring and links) have a distinct relationship to each other .
Obvious first is the fact that the horseshoes be larger in overall width than the ring; otherwise, there is no puzzle .
The ring should be within a specific acceptable ratio with the horseshoes -- ring diameter to horseshoe overall width and individual leg width as well; ie, if the ring is slightly too large, the solution will evolve too easily; if the ring is slightly too small, the solution may be almost impossible to solve, as well as from having the horseshoe legs too wide . (at the minimum, the ring diameter has to be at least slightly larger than the width of two horseshoe legs side by side)
The following horseshoe puzzle is one I've created for my collection . I've added a ring which is almost at the absolute minimum of diameter in ratio to the working of the puzzle . Normally, a nominal ring size would be to allow the ring to travel halfway up the overall width of one horseshow, giving the puzzler, at first try, the false impression that this would be the way to go, as obviously naive as that would seem .
But I chose this ring to make the puzzle especially difficult .
Finally, the third element in this equation : the chain links . Their overall diameter size isn't really that important, as long as they are aesthetically homogenous with the other elements . . . nothing looking too much out of synch with another . They should also have a smooth flex to them (ideally, links from a dog's choke chain) -- nothing that would enable them to 'kink' in the middle of the solution maneuvers .
Although I've used split rings at the horseshoe ends (for easier mounting of the links), I still consider them as part of the link chain . Nominally, there should be no more than three links between the horseshoes . Here, because of the very small diameter of the chosen ring, I've added a fourth link for more flexibility .
There are some metal horseshoe puzzles being sold on the Internet with welded links at the horseshoe ends . I personally think this unnecessarily adds to the puzzle's level of difficulty to an already difficult procedure . The nominal 'flex factor' calls for a loose end link .
Start by tilting the top horseshoe away from you and down .
There are two ways the top horseshoe can come down: either in front of, or behind the bottom horseshoe .
This view shows the top horseshoe travelling behind the bottom one .
Either way, both methods take the top horseshoe on a downward travel which will still have to come to that 'critical cleavage event', as discussed further down .
This top view shows the continuing downward travel the top horseshoe is making, at the same time allowing the ring to encircle the right-hand leg of the bottom horseshoe .
Now take the left-hand leg of the top horseshoe and glide it through the ring .
Here you can see a void forming between the two horseshoes .
What is now being experienced is called the 'critical cleavage event' ; the further down the top horseshoe travels, the more pronounced this cleavage progresses .
You are witnessing the deviously, mystical wonder of this puzzle .
This view shows you the same move, but with the top horseshoe travelling in front of the bottom one . This is accomplished by letting the top horseshoe drop towards you instead of away from you after gliding its left-hand leg through the ring .
Either way (towards - front, away from - back) the 'critical cleavage' still forms the same way .
From this point, all you need to do is to bring both horseshoes together .
Now you can just slide the ring off from either side .