One trait that distinguishes the expert declarer from the run-of-the-mill declarer is that he does not relax his vigil in the so-called easy hands. The expert always worries about what might happen to him if the adverse cards are distributed unfavorably.
Here is a typical case where it would be easy to go wrong. Let’s say South wins the opening club lead with the king and leads a low trump. West follows low, and dummy’s jack wins, East showing out.
That is the end of the road
for declarer, because sooner or later he must lose two trump tricks and go down one. He could attribute this to bad luck, but the fact is that he himself is responsible for losing the slam.
South can see from the outset that six diamonds is icecold if he loses only one trump trick, and that the only way he could lose two trump tricks is if the opposing diamonds are divided 4-0.
Such a division occurs in only one deal out of 10, and normally this possibility would be negligible compared with other dangers that might confront declarer. But here there is no other threat on the horizon, so South should focus all his concentration on the unlikely -- but possible -- 4-0 division.
Accordingly, he should win the club lead in dummy and play a low trump to his king (or win the club in his hand and play the king of diamonds). After East shows out, it is not difficult for declarer to limit himself to one trump loser. West’s 10-9-4 can easily be trapped later by leading twice toward dummy’s Q-J-8.
It is true that initiating the diamonds by playing the king first would not succeed if East had the A-10-9-4, but in that case declarer could not make the contract whatever he did.
Tomorrow: Test your play.