@JeremyECrawford do you need line of sight to cast counterspell on a creature? Or if you hear it using verbal components, is that enough?

— Jason Austin (@JasonAu40737688) September 26, 2016

Counterspell: take a look at the "Casting Time" entry. You need to see the creature casting the spell. #DnD https://t.co/tVDvXnSG74

— Jeremy Crawford (@JeremyECrawford) September 27, 2016

@JeremyECrawford Follow up: any way of knowing which spell is being cast? eg avoiding using your Counterspell on an Acid Splash

— Conor (@IcecreamGenius) September 27, 2016

My rule of thumb: if you perceive a spell being cast (V, S, or M) and it's on your spell list, you know what spell it is. #DnD https://t.co/BzkGO7ZZLT

— Jeremy Crawford (@JeremyECrawford) September 27, 2016

@JeremyECrawford Spell list as in your own personal list or the list for your class?

— Jordan Severns (@Jordan_Severns) September 27, 2016

My rule of thumb: if a spell is on your class's spell list, you can identify it when you perceive it being cast. #DnD https://t.co/OUKB7S9yOT

— Jeremy Crawford (@JeremyECrawford) September 27, 2016