[Philip]

I've seen a fair number of the village smith and late military daos with attempts to stabilize the disc guard when it got loose. One way of doing it was to drive thin wood wedges into the gap on either side, trimming the tag ends flush with the frontal surface of the guard. I've also seen small-diameter cord wrapped and tied behind the guard, the ferrule then being driven forward to cover it. The ring-pommel hilted dadao or falchions were kept in leather scabbards which were split at the dorsal side to allow easy withdrawal, so weatherproofing was not in the cards here. In fact, the Vietnamese often dispensed with scabbards completely with these knives, instead slinging them over the back like a carbine via a thick cord knotted through the ring, the other end having an iron hook that went through a small hole drilled in the dorsal peak of the blade. When worn in this way, the blade tended to rotate outward so that the edge faced away from the owner's body.

At least these guards, if not carefully fitted-up, merely loosen instead of falling off. I've had to restore the hilts on several Ottoman shamshirs and kilijs over the years, and because of the bulbous pommels the guards don't slide forward onto the tang to lock up against the blade shoulders as with most other swords. They are put on from the front, and an adhesive resin holds the langets into recesses in the grip. When the mastic gives way, these things can loosen or become detached.