What's done is done

It was a friendly rubber game to honor the newly enobled Thane of Cawdor, one Macbeth, at his castle.  King Duncan and his son Malcolm were playing against Macbeth and Lady Macbeth.  The night had not gone well for the hosts.  A steady progression of games had been made the other way and playing for 1 florin a 100, they were losing heavily.  What with the costs of the banquet and the new robes Macbeth had to purchase and gifts to bestow on his new administrators, they were facing financial ruin.  The scheming hostess suggested quadrupling the stakes for the last rubber and that was agreed by all.  A slam, preferably a grand slam, would wipe the slate clean and allow them to greet the new day joyously and at peace with all Scotland's people.

The rubber was finally going their way and with a game already, Lady Macbeth picked up these cards: ♠ AQ654 ♥ A2 ♦ KQJ ♣ T83 and heard her husband call 1♣.  She responded 1♠ and opener bid 4♠.  Here, she took over by bidding 4NT, the new Dunsinane convention which asked how many aces he had.  At this point, the young Malcom butted in with a bid of 5♦.  Macbeth was beginning to view his hand (♠ KJ32 ♥ KQJ4 ♦ A9 ♣ KQ7) rather less favorably now, especially holding the "curse of Scotland", the ♦9).  After all, his good (or even not-so-good) wife hadn't promised all that much with her 1♠ bid.  Perhaps it would be best to suppress an ace so that she doesn't get us too high.  The rules were easy to remember: double even, pass odd.  He therefore doubled to show zero aces.

From his wife's point of view, he must have both the missing aces – how else could he possibly jump to game opposite a simple change of suit at the one level?  She confidently bid the grand slam and King Duncan who, on account of his rank, was not required to be polite to his hosts, doubled.  Not to be outdone, Lady Macbeth redoubled and there it stood.  The play was straightforward: there was no place to park three losing clubs and down the slam went.  "How could you give me the wrong number of aces, Sire?" she asked without a hint of her usual deference.  "I thought perhaps I had overbid before with my jump to game," he responded lamely.  "Things without all remedy should be without regard: what's done is done," was all she would say.

After that, they lost the final rubber and were now in deepest despair.  Lady Macbeth was already planning dastardly deeds during the night as the only way to escape their impending financial ruin.  But as they took their leave of their guests, she could be heard emphasizing the point from that fateful auction to Macbeth: "To bed.  Come, come, come, come, give me your hand. What's done cannot be undone. – To bed, to bed, to bed!"

For some reason, Shakespeare neglected to mention the bridge game, but he did manage to use those excellent quotations in the famous "Scottish Play."

What's done is done is a rule I like to abide by and one that I try to impress on my partners.  I usually refer to it as the Principle of No Undos.  Once you've made a particular bid (unless it was a psyche), you must treat your hand as having the strength and shape as described by that bid for the rest of the auction.  Every further question your partner asks must be answered truthfully within the "box" that your bidding has described. 

Usually, it's when you've made something of an overbid where you are apt, like Macbeth, to get cold feet.  But it can happen equally well if you've underbid your hand.  You mustn't now try to "catch up" else you will likely confuse partner hopelessly.  All you can do is accept any invitations that come your way.