What can go away?

In general, the play of a bridge hand is a race between the declarer trying to set up enough tricks to make his contract and the defenders trying to their tricks first. It's a bit more obvious what's going on in a no-trump contract, but the principle remains the same.

Most declarers start out with a number of losers that they have to reduce to a particular allowable number. Of course, you may prefer to think of establishing winners instead--particularly in a no-trump contract. Some techniques such as finessing and squeezing are mostly concerned with establishing winners as opposed to decreasing the number of losers. Henceforth in this article, I will be discussing loser-elimination in suit contracts.

We normally think about reducing the losers in the master hand--the one with the long trumps. However, in a dummy reversal, the master hand is the one with the shorter trumps and the "dummy" is the one with longer trumps. Sometimes, the designation of master/dummy is somewhat arbitrary when the suit lengths are equal. Obviously, the location of the actual declarer (and that of the face-up hand) is irrelevant here. There are two primary techniques to eliminate losers from (the master) hand: ruffing, i.e. trumping losers in dummy, and discarding them on dummy's winners. A cross-ruff is a hybrid strategy: ruffing hand's losers in dummy and dummy's losers in hand. There's one other hybrid strategy and I'm not sure it has a name: it consists of discarding dummy's losers in suit A on hand's winners in suit B and then ruffing hand's losers in suit A in dummy. I'm just going to call this technique the hybrid plan and note that it's unusual.

Anyway, where am I going with all of this? It's because I believe that the major strategy for the defenders of suit contracts consists of two different tactics: (1) getting their own ruffs; and (2) figuring out what can go away, and ensuring that those potential tricks don't disappear before they can establish them. Along the way, of course, they will be cashing winners and switching leads as appropriate to best attack suits. Although I figured this out long ago, I still make the same mistakes of allowing tricks to disappear. But you shouldn't ever let it happen!

Here's an example from a recent BBO speedball tournament:

Kim, my favorite partner in all things including bridge, did well to put me on lead at T2. What should I switch to? Given the dummy, I diagnosed that the safest would be diamonds. But I forgot to ask "What can go away?" Based on the auction, any tricks we had coming in diamonds couldn't go away. That was declarer's second suit. It had to be at least four cards long since she didn't have four spades. But it might be longer. In that case, there was a danger that one (or two) of dummy's clubs might go away. A switch to clubs at trick 3 was the proper defense. Declarer could still make the contract but it wouldn't have been quite so easy. Unfortunately, many of our teammates didn't do so well as our opponents and we ended up with only 37% on this board. We still had a 73% session but +50 on this board would have put us into first place.