Markings on a Chinese sword?
 

Was this etched marking done by a westerner or is it original to the blade?
It either "SSD" or "550" :confused:

Thanks in advance for your help.

Not trying to make things more difficult. But have you considered that it may be SSII, as well?

Interesting thing! I've had a very similar one years ago, also with a similar marking and the same closed curl on the dorsal quillon.

I bought it when I was living in Beijing, the collector who sold it to me said it were Guomintang military markings, but I've never been able to verify this.

See attached a picture of the one I had.

The guards on these look like they're recycled from a Western-style military sword. I don't know any candidates for a donor.

Helleri, "SSII", is a possibility.

Peter, thanks for posting the photo. It provides a probability that the etching is original to the blade.