Computer simulation helps with leads

Anyone who has played with and against robots at Bridge Base

Online will know that their opening leads are imaginative. Against three no-trump, a minor-suit singleton has been chosen several times!

Nearly 10 years ago, Englishmen

Taf Anthias and David Bird used software to analyze opening leads.

They took numerous hands and randomly dealt the other 39 cards to satisfy the constraints of the auction. Then they calculated which leads work best at Chicago and teams (where overtricks don’t matter), and which at matchpoints (where overtricks are very important). Their conclusions can be found in “Winning Notrump Leads” and “Winning Suit Contract Leads” (Master Point Press).

Some of the conclusions were predictable, several surprising. Look at the West hand in today’s diagram. South opens one no-trump, and North raises to three no-trump. What would you lead?

The authors point out that in this auction, East-west will average 14.4 cards in the majors to the other side’s 11.6. So, lean strongly toward a major. They found that even a passive lead from a short major worked better than from honor-fourth in a minor.

In this example, the heart ace beat the contract 27.8% of the time, which was 8% better than a diamond. At matchpoints, the heart ace was still best.

In this deal, the heart ace is the only winner. South takes the second heart and drives out the club ace, but East establishes his hearts. Declarer has only eight winners (one spade, two hearts and five clubs), and if he takes the spade finesse, he goes down two.

A diamond lead, though, is too slow.