|5||0 or 3 aces|
|5||1 or 4 aces|
|5||2 aces of the same color or rank|
|5||2 aces of dissimilar color and rank|
Specifically, the 5 response shows one of the following pairs of aces:
And the 5 response specifically shows either:
A 5NT rebid by the 4NT bidder is king-asking, the responses to which are the same as regular Blackwood.
From the late Edgar Kaplan:1
"Opener learns that he is missing an important ace, and cannot make a grand slam. The 5 heart response shows two like aces: probably, from opener's point of view, spades and clubs (like in color), possibly diamonds and clubs (like in rank).
"Had responder held the spade and diamond aces, he would have responded 5 spades. Opener, looking at his own ace of hearts, would know exactly which unlike aces responder held, and would confidently bid 7 spades."
Roman Blackwood was created by the famous Italian Blue Team in the 1960s.
1 Kaplan, Edgar. Winning Contract Bridge. New York, Fleet Publishing Corporation, 1964.
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