Blackwood convention Blackwood convention In the partnership card game contract bridge, the Blackwood convention is a popular bidding convention that was developed by Easley Blackwood. It is used to explore the partnership's possession of aces, kings and in some variants, the queen of trumps, to judge more precisely whether slam is likely to be a good contract. Two versions of Blackwood are common: "standard" Blackwood, developed by Easley in 1933, and "Roman Key Card" Blackwood ("RKC" or "RKCB"), named for the Italian team which invented it. Standard Blackwood enables one partner to count partnership aces and kings in general. Key card variants
Chess tactic would prefer to pass and make no move, but a move has to be made, all of which weaken his position. Situations involving zugzwang occur uncommonly, but when they do occur, it is almost always in the endgame, where there are fewer choices of available moves. "Zwischenzug" (German for "intermediate move") is a common tactic in which a player under threat, instead of directly countering, introduces an even more devastating threat. The tactic often involves a new attack against the opponent's queen or king. The opponent then may be forced to address the new threat, abandoning the earlier attack. The