What is a cue bid in bridge?

A cue bid in bridge is a bid that conveys certain information about the hand. It is typically used in response to partner's opening bid or overcall to provide specific information about the bidding hand. Here are some key points regarding cue bids:

1. Meaning: A cue bid is a bid that shows a control (ace or king) in a particular suit. It tells partner that the bidder holds either the ace or king of the agreed suit.

2. Purpose: The purpose of a cue bid is to help the partnership determine whether to bid for slam (a contract of 12 tricks) or to stop at game level (a contract of 10 tricks). By showing control in certain suits, the bidding partners can evaluate their combined hand strength and decide how high to bid.

3. Timing: Cue bids are made after partner opens the bidding (or overcalls) with an artificial bid, such as a 2C strong club opening or a 1NT opening bid. It is not made in response to a suit opening bid.

4. Suit Hierarchy: Cue bids are made in a specific hierarchy to convey information about the control in different suits. The highest suit bid shows the highest-ranking control, followed by the second highest suit bid for the second-highest ranking control, and so on.

5. Level of cue bid: The level of the cue bid restricts the possible range of the cue bidder's hand. For example, a cue bid at the three-level typically promises at least a first-round control (an ace or a void) in the suit bid, while a cue bid at the four-level often promises an ace or void and some additional controls.

6. Cue bidding sequences: Cue bids are often used as part of a sequence to exchange more information. For example, after partner's strong club opening, a cue bid of 4C might show the ace of clubs, while a subsequent cue bid of 4D might show the ace of diamonds.

Overall, cue bids are an important tool in bridge bidding, aiding partners in evaluating their combined strength and determining an optimal contract level.