When today's South zoomed into six spades, East doubled, conventionally asking West for an unlikely opening lead - often the lead of the first suit dummy bid. The aim of this "Lightner" double was not to score more points but to give East-West a chance to beat the slam. But South figured out what the double meant. He ran to 6NT, and West hammered that.
When West led the king of diamonds, South took the ace, finessed with the jack of clubs, and ran the spades. The last spade squeezed West in three suits: He had room for five cards and had to save three clubs, else declarer would run dummy's clubs. So West discarded the queen of diamonds.
South then produced the jack of diamonds, squeezing West again. When West bared the king of hearts, South took the ace of hearts and claimed. Making seven!
West snarled: "You induced the man to run from six spades, which we might have beaten, and now instead of being at worst minus 1,430, we're minus 1,880."
"If you don't double 6NT," East flung back, "he may place me with the king of hearts and try the finesse."
I think East's double was righteous, not riotous. South would surely make six spades without the double since West would lead the king of diamonds. I have less sympathy for West's speculative double of 6NT, which helped South in the play.