LEARNING CENTER

4. 10. This is the safest play you can make. Anything else is dangerous. There is no reason to think partner has the J (just look at the full deal). There is no need to do anything aggressive/dangerous--dummy has nothing for you to worry about. Play the 10 now and continue to make safe plays later--for at least down 1 (maybe even down 2). The full deal:

	J654  Q65  A42  A65
9  J983  Q753  10832		K108  A72  10986  KQ4
	AQ732  K104  KJ  J97

5. 6.

Dummy "screams aggression." Declarer is known (from partner's Q lead) to hold the K. From the bidding he is known to have all the missing spades. Your partner has the A. If you go passive, declarer will draw trump and knock out that A. Dummy's hearts will be good for potential diamond discards. You shift to a low diamond, hoping partner has the Q--to knock out the A while partner still has the A. If declarer has the Q, there is nothing you can do anyway--he always has 11 tricks (6 spades, 3 hearts, A and K). The full deal:

	AJ64  KQJ10  AJ3  106
--  A983  Q872  QJ975		532  542  K106  A842
	KQ10987  76  954  K3

After your diamond switch, partner's Q knocks out dummy's A.
When partner wins his A, he plays a diamond and you take the setting tricks.
Without a diamond switch, declarer makes 5 (throwing diamonds on hearts, as you knew would happen).

1. . There is no need for an aggressive club switch; dummy's diamonds aren't likely to be of any use for discards. On the other hand, a trump switch is called for. If declarer has more than 2 hearts, he will want to trump hearts in dummy. You can prevent that by playing a trump now, and one later if another heart is played. This is why you won Trick 1 (you knew what to shift to and if partner happens to have Qxx, the spade plays should come from you, not partner). The full deal:

Vul: Dir:	J4  87  A7632  Q643
87  QJ1052  J84  982		532  AK3  Q109  KJ107
	AKQ1096  964  K5  A5

Your trump shift and subsequent trump play leads to down 1.

1. or . This is a passive play, indicated by dummy and the bidding. For his jump to game, declarer likely has both black aces. Shifting to either minor is fraught with danger. This is a RED-light situation--any aggressive play is likely to cost a trick. Just get out of your own way and sit back and wait for your tricks.  The full deal:

	KQ4  KQ3  AJ82  Q107
5  J10982  Q763  982		732  A764  K95  KJ4
	AJ10986  5  104  A653

Declarer always can make his contract, but a minor-suit play at trick 2 would give him an undeserved overtrick. After your major-suit return, declarer will throw a diamond on a heart and eventually lose 2 club tricks. A club switch will cost you a club trick. A diamond switch allows declarer to set up 2 extra diamond tricks (he then throws away 3 clubs on dummy's red suits). At matchpoint scoring, allowing that 11th trick as opposed to holding it to 10 is the difference between a bad board and a good one.

7. 2. Dummy's hearts are screaming for aggression by you. Once trumps are gone, that heart suit is sure to provide discards for declarer. If he has clubs to lose, they will go away on the hearts. You must shift to a low club to try to get the tricks you have coming your way. The full deal:

	AQ65  AQ1084  4  Q83
7  K9  J109862  A974		42  7653  AK73  KJ2
	KJ10983  J2  Q5  1065

Even if declarer didn't have the J, the hearts would still get set up somehow. On this layout, if you switch to the 2, you collect the first 4 tricks for down 1. If you do anything else, declarer easily takes 12 tricks (discarding all of his clubs on the hearts).