A careful declarer will expect the worse and prepare for it.
Sometimes it just needs a slip by an opponent. Take a look.
Scoring: Matchpoints (Pairs)
Hand #47
Dlr
N
Vul
N/S
QJ
KQ104
J3
J8732
A87
986
9872
KQ5
109542
J3
KQ65
64
K63
A752
A104
A109
West
North
East
South
Pass
Pass
1NT
Pass
2
Pass
2
Pass
4
All Pass
BIDDING: North-South
reached game after using the Stayman convention to find their heart fit.
PLAY: West made the best
lead of a low diamond and declarer saw he must lose a spade and a
diamond so he could only afford to lose one club. This didn't
seem to be difficult because the probability of East holding one of the
missing honors was 75%. However, it was possible for both the
king and queen of clubs to be in the West hand so declarer continued
with that in mind. He won the diamond opening lead followed by a
spade toward dummy. West won the ace and led a second diamond to
East's king. Without much thought, East led a second spade to
dummy's queen. Now declarer only had to play the king and ace of
hearts followed by the spade king and diamond ten to eliminate the
pointed suits. Next declarer drew the last trump with dummy's
queen followed by a low club to his ten. West won this but had to
return a club or give declarer a ruff/sluff.
The error was committed by East. Playing too quickly, East should
have wondered why declarer wasn't drawing trumps. An elimination
play was a strong possibility and all East did was help declarer.
He must return a club after winning the diamond trick. This would
allow West to win and exit safely.