Playing five-card majors, South opened 1!, West doubled, and North raised pre-emptively to 4!. East doubled, showing values but no great suit, and West faced his first decision.
To my mind, 4NT - suggesting that his partner choose a minor - was clear- cut. East was unlikely to hold four spades when, rather than double, he could have bid the suit; so, as he lacks length in either major, there must be a good fit in a minor. West made his first mistake in passing, arguing that he had sufficient defence. He did, but 5 (even 6!) diamonds would have scored far better.
Now the second disaster: West led #A against 4! doubled, and East followed with the nine, suggesting four cards in the suit. West brooded: could a diamond continuation establish a possible queen in South's hand for a spade discard from dummy? Or would a black ace be better? His eventual choice of 4A was not a success and South was able to make a claim, conceding a club.
Could West have come to a more logical conclusion? Arithmetic would have helped. Having assumed that East did not hold four spades, and judging that he held four diamonds, the fact that N-S were playing five-card majors meant that East held at most two hearts. Therefore declarer held at most one club and 2A at trick two would have confirmed this analysis. West could now safely continue clubs and, in the fullness of time, the defenders would have come to two spade tricks. A poor substitute, of course, for their minor suit game.Reuse content