Watched an instructive hand today. Bidding with opponents passing throughout was 2NT-3C 3H-4NT 5S-7H swish. Making. Cold for 7NT but about 25%, so the bidding was perfect. At the conclusion of the round I asked the 2NT bidder how he knew what 4NT meant, quantitative, Blackwood for notrump, or BW for hearts. (they play RKC) He said it had to be BW for hearts as trump. Never quant, never for notrump. If for notrump responder would have bid 4C Gerber, which would also have guaranteed a 4 card spade suit. Question: Do you and your partner have such clearly defined agreements?