chinese dao with two blades for comments
 

It is quite short it is 63cm long,the blade measures 40cm, 3 cm wide, the second blade 28cm long

the last one

I'd say modern. The style of fittings and grip, and blade are consistent with modern Chinese fakes, and I have never seen a genuine twin dao in this style. (I have seen 2 published examples in a book riddled with errors, obvious fakes listed as genuine, and major misidentifications, but given the overall quality of the source, I'm not willing to consider those "genuine".) In addition, I've seen plenty of fakes of this type on ebay. Unless there is a very good reason to think this is genuine, I'd call it a modern fantasy sword or a fake antique, depending on how the seller represented it.

There are historical example of twin dao, but they're mirror-image twins in the one scabbard.

I do not think that it is modern
the galuchat on the scabbard is quite worn, sign of anciennetee, as well as the Interior of the worn sleeve, the patina that i was on the blade before cleaning...and quality of work, it is very thin and neat

This is not a sword of antiquity. I would suggest 1980s at best.

Disregarding the second hidden sword, the sword size and profile is found in antiquity.
The method of manufacture and materials in the sword shown is considered "New".

Gavin

ok thank gavin

Yes, Gavin is correct. The work is all modern.

Interestingly, there are period examples of these double swords, but the majority are recent. I have seen two antique examples, and both appeared to be from the late 19th early 20th c. period. They are copies of regulation duan dao, but they have a bit of a novelty feel to them and may have appealed to foreigners.

Mine has what seems to be a recycled jian blade next to the longer, hefty, duan dao blade.

The copy posted is trying to match the style and period of the originals but the workmanship is a tell tale.
Josh