THE TRUMP COUP
Below are examples of a declarer play technique known as the Trump Coup.
Once you learn this method there is but one important principle to remember...
A spade is led followed by a diamond and West must play either the 5 or the queen of trump, allowing declarer to win the rest of the tricks. There is, of course, an appropiate applause by the spectators.
A trump coup is a situation where the hand on lead (usually the dummy) has no more trumps remaining but declarer's right hand opponent has a high trump honor onside. Since declarer cannot finesse, the only way to win the guarded trump is to force RHO to trump a card led from the dummy, allowing declarer to overruff. A trump coup cannot be achieved unless declarer has shortened the length of his trump suit to the same length as that held by his RHO. Additionally, declarer must be able to lead from the hand opposite his trumps in order to effect the coup.
Your contract is 4 and West leads the A.
It's too bad you didn't get a minor suit lead, right?
After West takes the third heart she leads a club, hoping her partner has the ace. You take it with the ace in your hand, and lead a trump to the dummy, returning a trump for a successful finesse. Unfortunately you find that West is out and you cannot finesse again.
This is an an excellent example of the Trump Coup where you must reduce the length of your trump holding to the same length as that held by your right-hand opponent.
Even though all the cards in dummy are good cards, you must ruff two of them to bring your trump length to the same as East's length in the trump suit. (When you must trump winners, the play is called a Grand Coup or sometimes a Royal Coup.)
Lead the K and overtake it with the ace. Trump a small diamond in your hand. That's one less trump in your hand. Lead a club to dummy and ruff a second diamond. That's the second time you have trumped, so now you and your RHO have the same number of trumps. Lead your last club to dummy so that the dummy is on lead and this is the position: (See how that works out for you?)
The contract is 6 and the lead is the T.
Since you have six trumps and RHO has five, you need to ruff once in your hand to reduce your trump holding to the proper length, right? You also have to be able to lead from dummy at the point when you have only the queen and ten of trump left in your hand.
When you play a spade to dummy and discover the bad split in trump, you can return a spade for a finesse, but then you will have to shorten your trump suit. Play the ace and king of hearts, discarding your last diamond, and lead another heart to ruff. Continue with clubs so that you reach this end position with the lead in dummy... and you have just executed a trump coup: