Suppose a bidder makes an unusual bid that is "alertable." The bidder's partner is then supposed to say "alert," and then field questions about the bid.

But suppose the partner fails to do this. Can the opponents ask for an alert?

What happens in the two opposite cases, if the opponents do ask for an alert and 1) the bid is alertable and the partner forgot to alert (opponents are wrongly deprived of information) and 2) the bid is not alertable (opponents may ask for and get unauthorized information)?

1 Answer 1


Law 20 of The Laws of Duplicate Bridge deals with review and explanation of calls. Quoting partially:

F. Explanation of Calls

  1. During the auction and before the final pass, any player may request, but only at his own turn to call, an explanation of the opponents’ prior auction. He is entitled to know about calls actually made, about relevant alternative calls available that were not made, and about relevant inferences from the choice of action where these are matters of partnership understanding. Except on the instruction of the Director, replies should be given by the partner of the player who made the call in question. The partner of a player who asks a question may not ask a supplementary question until his turn to call or play. Law 16 may apply and the Regulating Authority may establish regulations for written explanations.
  2. After the final pass and throughout the play period, either defender at his own turn to play may request an explanation of the opposing auction. At his turn to play from his hand or from dummy declarer may request an explanation of a defender’s call or card-play understandings. Explanations should be given on a like basis to F1 above and by the partner of the player whose action is explained.


  1. (a) A player whose partner has given a mistaken explanation may not correct the error during the auction, nor may he indicate in any manner that a mistake has been made. “Mistaken explanation” here includes failure to alert or announce as regulations require or an alert (or an announcement) that regulations do not require.
    (b) The player must call the Director and inform his opponents that, in his opinion, his partner’s explanation was erroneous (see Law 75) but only at his first legal opportunity, which is
       (i) for a defender, at the end of the play.
      (ii) for declarer or dummy, after the final pass of the auction.

Alert procedures and requirements are prescribed by the Regulating Authority, such as the World Bridge Federation or the American Contract Bridge League.

The ACBL has a document explaining alert procedures, as well as a document that advises directors how to deal with failures to alert.

So, to answer your questions:

  1. Opponents do not ask for an alert, but they may ask you for an explanation of your partner's bids when it is their turn to bid or play.

  2. An unexpected alert, or alternatively a failure to alert when expected, by your partner presents unauthorized information to you. Not only may you not take advantage of this information, you are required to avoid actions that are suggested by the information. From Law 16, which deals with unauthorized information:

B. Extraneous Information from Partner

  1. (a) After a player makes available to his partner extraneous information that may suggest a call or play, as for example by a remark, a question, a reply to a question, an unexpected (i.e., unexpected in relation to the basis of his action) alert or failure to alert, or by unmistakable hesitation, unwonted speed, special emphasis, tone, gesture, movement or mannerism, the partner may not choose from among logical alternatives one that could demonstrably have been suggested over another by the extraneous information.
    (b) A logical alternative action is one that, among the class of players in question and using the methods of the partnership, would be given serious consideration by a significant proportion of such players, of whom it is judged some might select it.
  2. When a player considers that an opponent has made such information available and that damage could well result, he may announce, unless prohibited by the Regulating Authority (which may require that the Director be called), that he reserves the right to summon the Director later. The opponents should summon the Director immediately if they dispute the fact that unauthorized information might have been conveyed.
  3. When a player has substantial reason to believe that an opponent who had a logical alternative has chosen an action that could have been suggested by such information, he should summon the Director when play ends (It is not an infraction to call the Director earlier or later). The Director shall assign an adjusted score (see Law 12C) if he considers that an infraction of law has resulted in an advantage for the offender.
  1. If partner fails to alert a bid (or otherwise gives an erroneous explanation of one of your bids), and you are the declaring side, you must call the director immediately after the last pass ends the auction. If you are the defending side, you must call the director immediately at the end of play.
  • 1
    +1 for a clear explanation, and if possible another +1 for recognising that there are other authorities besides the ACBL. Commented Aug 27, 2017 at 15:04
  • 1
    However, a perfect answer would have indicated that asking the question when it is your turn to bid is not risk-free; you are indicating to your partner that you have reason to believe the bid was not natural, which could itself be unauthorised information. Commented Aug 27, 2017 at 15:14
  • A minor but significant point; the request for an explanation should not be leading in form. That is, one should say "what did the 2 Heart bid mean?" not "was two hearts a transfer?" Never suggest a possible answer in the question, as if the answer is 'no" you have told your partner what you were thinking, which may be unauthorized information. Also, do not ask if you already know the answer, or if it will make no difference to your actions, or to alert your partner to the situation. Commented Apr 12, 2019 at 2:54
  • @DavidSiegel I will note that there is some difference opinion as to the first two clauses of your last sentence. In particular, I know of player that (at least in high-level play) always ask about opponents' bids (when alerted or not clear from their convention cards) so as not to give partner unauthorized information about their hand / thought process.
    – ruds
    Commented May 10, 2021 at 2:37
  • I also know several who claim that they always ask about opponents' bids in [situationX]. And a fair percentage of them do. The rest somehow magically forget to ask with a flat 2-count, even if they do it the other 90% of the time. If you choose this option, you must be completely ethical about it, same as the STOP card users had to do it even after 1S-2NT-STOP 4S and ... STOP-7NT. Having said that, I have three cases where I always ask: Alerted overcall of my weak NT; "when can it be short?", and cuebids of our preempts (I play "one-under splinter" and "NLD doubles", 1-U wins).
    – Mycroft
    Commented May 11, 2021 at 16:22

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