Key Card Blackwood

A version of the Blackwood convention in which the king of the agreed trump suit is counted as an ace, making for a total of 5 Aces. The responses are:

5 - 0 or 5 Key Cards

5 - 1 Key Card

5 - 2 Key Cards

5 - 3 Key Cards

5 - 4 Key Cards

If there is no agreed trump suit, some pairs play the last suit bid before the 4NT call is the key suit.