1430 or 1430 RKCB A mnemonic for a variant response structure to the Roman Key Card Blackwood convention. It represents '3 or 0' and '1 or 4', meaning that the lowest step response (5 ♣) to the 4NT key card asking bid shows responder has three or zero keycards and the next step (5 ♦) shows one or four.
0–9 3014 or 3014 RKCB A mnemonic for the original (Roman) response structure to the Roman Key Card Blackwood convention.
