No serious tournament players now use plain old Blackwood. It has been replaced by the extended version known as Roman Key-Card Blackwood. The reason for this is that the king of trumps is just as important a card as any of the outside aces, for who wants to be in a slam that at best requires a successful finesse against the king of trumps? Roman Key-Card Blackwood allows you to avoid such embarrassingly silly contracts.
But Roman Key-Card Blackwood is not a simple system. Although the first responses to the 4NT bid are straightforward, the follow-up action is tricky and comes in several flavours. You will need considerable partnership discussion before you can safely use Roman Key-Card Blackwood. Even my (of necessity) rather lengthy description of Roman Key-Card Blackwood only covers the basics.
But there is a much simpler alternative that offers most of the benefits without any complexities. It is called "Five-Ace Blackwood", and is presented here.
There is just one small change from the ordinary Blackwood that you will already be familiar with. The king of trumps ccounts as a fifth ace. We call the four aces and the king of trumps "key cards" in the write-up below.
The responses to Five-Ace Blackwood are exactly the same as with plain Blackwood,
with the addition that
In some bidding sequences there may not be an explictly agreed trump suit. If that happens, then the last suit bid by the partnership before 4NT is taken as the trump suit for the purposes of determining which king is to be counted. If no suit has been bid then plain Blackwood applies.
This is exactly as in standard Blackwood, with the obvious difference that the king of trumps is not counted. There are thus three side-suit kings. After the 5NT king ask, responder replies:
This conventions is just as easy as plain old Blackwood both to play and to remember, yet it will improve your slam bidding enormously. It is highly recommended.
Author: Chris Burton
Gravesend Bridge Club