In Chinese (I don't know if it's Mandarin, Cantonese or another dialect - probably Mandarin) it's called Erhu, but D's family alwasy calls it a two string.

As you can see, the bow is attached between the two strings. Sound is created by drawing the bow across the strings, just as in a violin. Different pitches are created by pressing the strings down in various spots, just like in a violin or guitar.

Unlike a violin, it sounds like a cat being killed.