No, this isn’t a quiz; I’ve owned this instrument for years, but I’ve no idea what it is!
I acquired it from my mother-in-law’s antique shop; she didn’t know what it was either. At the time, I did make a number of enquiries around various local music shops, but to no avail. Then the internet was invented, and even scouring the fount of all knowledge, Wikipedia, I’m none the wiser. It’s about the size of a flat-backed mandolin, and like the mandolin, has four courses of strings, but unlike the mandolin, each course has three strings, not two. Four course, triple strung instruments are generally referred to as tiples and are typically (I just had to say that) guitar-shaped, rather like a ukelele, and of Puerto Rican origin. For some reason, I have always suspected that this particular instrument was of eastern European origin.
So if anyone stumbles across this, and can shed any light, please get in touch.