Expert spot usage
I was commentating on BBO when this deal arose in the 2017 European Championships:
South opened 1NT, 15–17. I see only 14 high-card points, but as frequently happens, players upgrade for good five-card suits. Perhaps the abundance of queens and jacks should have prevented such optimism.
Anyway, game would have been reached regardless.
After 1NT, North transferred to hearts and then offered a choice of games with 3NT. South chose 4♥ and West got off to a good lead – a low club (this pair leads low from x–x–x). When East doesn’t double the 2♦ transfer, that is a slight nudge away from a diamond lead, making a club a slightly better guess. Leading the ♠A is never an option; a trump is possible.
Declarer played low from dummy and East won the ♣K. Now what?
From our catbird seat, it is easy to see three more defensive top tricks. But how would East know to dangerously switch to spades? Declarer could have ♠A x x or even ♠A J x, where this would be costly. Instead, East returned a normal ♣10 – maybe partner had ♣Q–x–x. Declarer won, West playing the ♣6.
Declarer led the ♥Q and West played the ♥9. What’s with the unnecessary high club and heart spots?
Expert defenders use lots of subtle suit-preference signals. Because those club and heart spots make no sense for uses like count or attitude, they should send a message about the other suits (spades/diamonds). West’s high cards in both cases, screamed spades. East got the message and, just in time, switched to spades upon winning his ♥A, setting the contract one. Had East stayed passive, declarer would have made an overtrick by throwing dummy’s spades on his good diamonds.