Yep, pommel rings have always been associated with dadao, and I have never seen a second example of a jian with a pommel ring. A real puzzler, isn't it?
Another unusual point is that the guard, while bearing some similarities to the dadao's guard, it's made of iron, not brass, like nearly every other jian and dao I've seen.
The sheath and hilt of the jian is late 20th century - absolutely new. So I guess the maker of the sheath and hilt took a fair bit of artistic license in creating them. I think the only old parts were the blade and the iron guard. The rest must have perished. Judging from the iron guard which is bereft of any decorations, the lost old fittings could have been very spartan as well.
Apologies to Bill for hijacking the thread.
