A Three-way Example
A 9 8 7 5 2
A Q
K
Q J 10 5
Q 10 4
J 7 6 5
10 7 3
K 7 2
6 3
K 10 8 2
J 5 4
9 6 4 3
K J
9 4 3
A Q 9 8 6 2
A 6
There are actually three strains possible on this hand - notrump,
spades, and diamonds - and North/South can make slam from only one side
in each strain.
Notrump
After a heart lead by West,
6 NT cannot make. There are
10 top tricks, and declarer will need to set up two more to make his
slam, but he needs to lose the lead to West in spades or clubs to do
this, at which point the defense can take a couple more heart tricks.
Declarer can run a strip squeeze against West to get an 11th trick, if
5 NT is the contract. Declarer loses the heart finesse and
wins the heart return. He then cashes the
♦ K,
crosses to the
♠ K and runs the diamonds:
On the last diamond, West can't part with a spade or a club, so must
part with a heart. Declarer then can play the
♠ A
and a low spade, forcing West to lead clubs.
So the most South can make in notrump is 11 tricks.
Declared by North, though,
6 NT plays itself.
Declarer can set up the two extra tricks he needs in either clubs or
spades.
Spades
Declared by North,
6 ♠ stumbles when declared by
North, after a club lead. The club lead breaks declarer's
communication to the long diamonds.
When declared by South,
6 ♠ rolls home on any lead.
For example, on a heart lead, declarer wins the ace, cashes the
♦ K, cashes the
♠ A-K, then starts running
diamonds, pitching the
♥ Q then clubs, lead to:
No matter when West ruffs in, South can get back to his hand with the
♣ A to finish running the diamonds.
If West tries to cut off the entries with a
♣ K lead,
that sets up too many tricks in the dummy - only the heart loser needs
to be pitched.
Diamonds
When South declares
6 ♦, West can lead a heart.
This breaks off the entry to the long spades, forcing South to
apparently lose three tricks. But that is an illusion - South can run
the same strip squeeze against West which allowed him to make 11
tricks in notrump.
But when North declares
6 ♦, East cannot profit from
leading a heart. Perhaps the club lead?
North wins the
♣ A, crosses to the
♦ K, and
back to dummy with the
♠ K. North finishes drawing the trumps,
crosses to the
♠ A, and ruffs a spade. Declarer still has
the
♥ A, and comes to thirteen tricks. A two-trick asymmetry!
Post-mortem
This one is a relative rarity - two suit contracts play better
from opposite sides. Usually, one side plays better in the
suit contract(s) and the other side side plays better in the
notrump contract.