Chip Martel, USA

A switch in time saves nine

One of the more difficult aspects of defence is to appreciate when it is necessary to change tack, particularly when it appears that you have made a good start. This is from the third session of the semifinals:

The auction in the closed room was virtually identical, East rebidding 2 spades as opposed to 2 hearts.
Both North’s led the four of spades, handing declarer his ninth trick.

In the match between USA and Denmark the same spade lead gave the Denmark +600 but declarer had to work much harder in the Open Room:

North led the ten of hearts and South won with the king and continued with the queen, North following with the two. South continued with the three of hearts and North won, cashed a fourth heart, declarer throwing two diamonds from dummy and spade from hand and switched to her diamond. Declarer won in dummy and ran the diamonds, to reach this position:

When declarer cashed the last diamond North had no answer. She pitched a club and declarer threw dummy’s spade, crossed to the king of clubs and played a club to the ace to flatten the board.
To defeat the contract South must switch to a spade at trick two – a tough play to find.
Suppose North had started with a fourth best two of hearts (by no means impossible, as you are hoping to find partner with something useful in the suit). Now South knows you have only four tricks in the suit at best and might find the spade switch.
Notice that it is not good enough to switch to a spade at trick three as declarer can win and play five rounds of diamonds, squeezing North in three suits!
Just for the record try and find a route to nine tricks if North leads his singleton diamond – I can’t!