Posted 2006-August-22, 17:05
I agree partner would have shown five spades if he had strength enough to bid at all. Therefore declarer has 5+ spades. Declarer would have bid spades before hearts with 5-5, therefore he has 6 or 7 hearts. He must be 5-6-2-0, 5-7-1-0 or 6-7-0-0.
If declarer has 7 hearts, he has already drawn trumps and can ruff two spade losers at leisure, losing only the top two spades (or losing only one if he has K♠). Therefore the only shape with a chance to defeat the contract is 5-6-2-0.
Declarer has no diamond losers (he will take the finesse if he needs it) and obviously no club losers. If he has K♠, he can simply lead toward it through your A♠ and make the contract by ruffing the third and fourth round of spades in dummy, setting up the long fifth card.
Tossing the A♠ on the trump leads gains a trick when partner has Q♠ but not K♠, because then partner can gain the lead (instead of you) to lead a trump and restrict the ruffs to one. This only defeats the contract when partners trump is the Queen, because with K♠ declarer will only have one top loser in spades. Partner's spades will also need to be strong enough to prevent a ruffing finesse in spades when dummy has only one trump: QT8x is minimum.
Conversely discarding A♠ lets an unmakeable contract slip through when declarer has QJTxx or a number of other combinations promoted to single top loser by the dump of A♠.
Would I drop A♠? No! Because if declarer had the kind of hand where dropping the AS helps (♠Kxxxx-♥AKxxxx-♦xx-♣v) he would have instantly seen the problem on the FIRST heart trick when I show out. He would see that it cannot cost to cross in diamonds and lead a spade towards his K before drawing a second trump, making certain of two ruffs in dummy (if I discard A♠ on the FIRST round, he will simply lead K♠, lose a spade to partner and win K♥ if partner can lead a trump from QJ remaining, crossruffing clubs and spades thereafter).
Don't drop A♠ unless you think declarer could not have worked this out. Also consider this: if you fail to find the drop of A♠ when it works, you can commiserate with all the other people who did the same thing, whereas if you drop A♠, and it turns out declarer was off Q♥ and the top two spades, you are going to look SUCH a duffer trying to explain it to all the other players who just sat back and watched their three tricks roll in ... hehe.
(note: QJxxx in original post edited to QJTxx, on further thought)
My bridge tip: never raise to 6NT a partner who thinks "rectifying the count" involves garlic, crucifixes and a wooden stake.