The shamisen is a stringed instrument from Japan. It is a type of lute with three strings and a long thin neck. The player plucks the strings, and the first string rattles against the wood as it vibrates.
The shamisen has no frets as we have on modern guitars, so the player must stop the strings with the left hand, using his or her own sense of pitch to determine exactly where to place the fingers. This is what violinists and cellists have always had to do.