OFTEN in a competitive auction nobody knows who can make what. The two traditional pieces of advice: “when in doubt, bid one more” and “the five-level belongs to the opponents” are contradictory. The side that holds the spade suit has a huge advantage, as on this deal from the European Senior Trials.
Over 1D North must decide how many spades to bid; playing weak jump overcalls he tried a simple 1S; the auction will not die, and he can better judge how high to bid when he has more information. The vulnerability was wrong for East to raise beyond the three-level: despite the five-card support his hand is full of losers. South might also make a pre-emptive raise to 4S, but he settled for 3S, giving West the opportunity to show extra distribution by bidding his second suit. When North bid game East decided that even a vulnerable a sacrifice would be cheap. The auction sounded unconvincing to North, so he doubled.
To beat 5S East-West must play clubs before the ace of hearts is dislodged, perhaps after cashing one diamond. To beat 5D North-South play hearts before the ace of clubs is dislodged, but North played two top spades. Iain Sime ruffed, drew trump and played a club to the king and ace.
The heart switch came too late. Declarer won the ace, finessed the nine of clubs, cashed the queen and returned to hand with a trump to discard dummy’s hearts and claim 11 tricks, a 15 imp gain when 4S made at the other table.