 In the "neck" positions (which use just less than half of the fingerboard, nearest the top of the instrument), the thumb rests on the back of the neck; in "thumb position" (a general name for notes on the remainder of the fingerboard) the thumb usually rests alongside the fingers on the string and the side of the thumb is used to play notes.The fingers are normally held curved with each knuckle bent, with the fingertips in contact with the string.If a finger is required on two (or more) strings at once to play perfect fifths (in double stops or chords) it is used flat.