How do you play a flat note on the violin?

You can play a flat note on the violin by placing your finger slightly closer to the nut (the small ridge at the top of the fingerboard) than you would for a natural note. This will make the string sound slightly flatter than it would otherwise. You can also play a flat note by using a vibrato technique, which involves oscillating your finger back and forth on the string while you bow it. This will create a warbling effect that can make the note sound flat.