If in dummy there’s a long, strong suit, the defenders’ need to win tricks quick is quite acute

Defences fall into two main categories: active and passive. The active defence involves trying to score tricks quickly by broaching new suits. Leading a new suit frequently costs a trick (it’s much better to play the second and fourth cards) so, all things being equal, you would prefer to play passively, giving nothing away. Active or passive – that is the question?

The nub is this: when (versus a suit contract) dummy has a long, strong suit, one that will provide declarer with discards for his losers, a defender must attack, trying to win tricks quickly. Dally and (trumps drawn) declarer will dump his losers on dummy’s suit. If dummy has no such long, strong suit, the defence should stay clear of new suits. Instead they can lead trumps (crucial if dummy has a ruffing value, but bad if it will pick up partner’s honours), or go completely passive.

Examples include making declarer ruff in the long hand (with trumps that will win tricks anyway), or giving declarer a high card that will always win.

In (A) there is nothing to fear in dummy: no long, strong suit that will provide declarer with discards for his losers. East is best simply returning a second club. Unless declarer is inspired, he will win ♣ K and lead ♠ 2 to ♠ K. He will now have to lose two trumps to West’s ♠ AJ and, in the fullness of time, a diamond to East’s ♦ Q (he will try ♦ 4 to ♦ J but the finesse will lose). Passive defence – down one.

In (B) dummy has a threatening heart suit. After East’s ♥ K has won, dummy’s hearts will provide declarer with discards – clearly in diamonds. East must switch to ♦ 2 at trick two (key play) in the hope West holds ♦ K. Here ♦ K will force out dummy’s ♦ A, declarer will lose to West’s ♠ A and the defence will take a promoted diamond trick plus later (when the finesse loses) ♥ K. Active defence – down one. The diamond switch at trick two was a risk East had to take on (B), but on (A) it would have let 4 ♠ make.