This “knot” or rather, absence of knot, was first seen on the Greek shipping tycoon Aristotle Onassis in 1989. Not sure if he is the inventor, but he is certainly the innovator. I have seen several ways to tie it (well only two) one is the Full Windsor base and the other is a Four-in-Hand base. Both end the same way, and both end up looking the same. I prefer the Windsor variation for two reasons: it is a firmer knot, and will knot come loose on it’s own, and it creates a symmetrical knot so it’s easier to keep the top of the Onassis horizontal. But like I said, it hardly matters, start it whichever way feels more comfortable to you.