Four-card Suits
This is one topic that wasn't in the original manuscript written near 20 years ago. It was only when I began playing bridge on the computer, where with a tap of the thumb I could see the play to each trick, that I began to see how valuable four-card suits are to defenders and how carefully they should be guarded. If any readers want to sneer at a computer, for God's sake, let me offer both a concession and a defense. Yes, the program I play is notoriously wasteful with good four-card holdings. Almost invariably a defender will discard his second highest card in his best suit at first opportunity, sort of to say, "Partner, I had a good holding here until using this card to tell you I had a good holding." I have no idea why it was programmed that way.
But if a computer program, with its automatic recording of every card played to every trick, made me aware of this common error, and on looking to live play, I find the error common there also, then the computer has served a valuable function. That's something you can't map out at your local club, even on sessions where there are hand records, especially when you're going over a hand while driving home. Now, however, OKbridge has combined automatic recording with live play, and the pattern of profligacy in regard to four-card suits was manifest there also.
When I decided I didn't want too many instances drawn from the strangely programmed game I often resort to and went to the most recent tournament on OKbridge, I found two instances of misuse on the second hand I examined. On the following day, I was to be the beneficiary of such misplay myself on OKbridge. So it is a common error, a very common one, and indeed, perhaps even the most common on defense -- certainly far more so than a sluff and ruff, which can induce something close to apoplexy. I am, let me be clear, speaking of mistakes, of a foreseeable mishandling the cards, not wrong guesses on opening lead, which is traditionally the most difficult play on defense to get right.
A reasonable question now is, why four-card suits. Why not three-card? Or five-card? Or even six-card? Well, there are two reasons why three-card holdings aren't going to get much attention here. One is that your partner may be able to guard the suit as well as you, which isn't impossible with a four-card holding where declarer also has four cards, but is far less likely. And the other is that the value of a three-card holding, if valuable it be, isn't so likely to be hidden. You may have Q J x or even Q x x and even a J x x is generally recognized as potentially valuable. One exception, I might say, is a twice-guarded 10. I once started collecting different ways a twice-guarded ten can become a winner (different ways, not just different instances). So I'd caution you against treating such a holding with disdain. Otherwise I haven't seen tricks wasted by foolish indifference to 3-card holdings. [Actually, I now have: just recently, I marvelled to myself at the frequency of not hanging onto two guards to a queen!]
As for five-card holdings, when you can see or have reason to believe declarer's closed hand has a five-card side suit where you also hold five cards, then, yes certainly, you don't want to discard down to fewer cards than declarer holds in that suit if you can help it. But this is far rarer than 4-card holdings battling each other. A few mathematical verities would drive that point home:
The Mathematical Table in the Bridge Encyclopedia tells us that if you have four cards in a suit, the odds of the remaining 9 cards dividing 3-3-3 are 11%. So it would seem that there's roughly a 90% chance that someone else at the table will hold four or more cards in that suit. And since you have twice as many opponents as partners, it would seem that there's about a 60% chance an opponent will have four or more cards in that suit. You couldn't come remotely near that with a 5-carder. Indeed, I would say off the top of my head that a four-card (or longer) suit in opposition to another four-card (or longer) suit is about 50 times likelier than two 5-card suits battling each other.
So the emphasis will be on four-card holdings. Now, when you have more than four cards opposite declarer's four-card suit, you can almost surely discard the excess down to four cards with impunity. People do tend to fall in love with their powerful suits. But the chances are slim that you're going to run that suit, even in no trump and you might as well discard the excess baggage when it comes to discards. However, then you want to be very careful about discarding below declarer's number. And this works in the opposite direction, also: if declarer is the one with the longer holding where you have four, you may not be able to match declarer's length, but that is certainly no less reason to hang onto your 4-card length.
So "four-card suits" will include holdings of five cards and six cards. Further, the term applies to the original holding, of course. If you and dummy start with four cards in the same suit, after two leads, that's still a "four-card suit" by my terminology, a four-card suit where you have to guard the fourth-round, or may have to.
Now of course, it's not always easy, for what do you do if you have two four-card suits, or even three, and must discard from one by trick two or three? No absolute rules can set forth, but there are a few pointers I would offer:
1. I would start with saying, keep the suit where you can see declarer has that many or more in dummy. Oh, there are times you can disregard that advice. If your highest card is lower than dummy's lowest, you're not going to capture any cards there and don't want to hang onto that suit just because you each have four. Also, when you're certain declarer has no entry to dummy, you may want to cut down on that suit. But by and large, I would make that my number one priority.
A close second is side suits where the bidding has indicated four or more cards where you have four. A minor suit opening bid would not qualify as promising 4 cards, nor, of course conventional bids and cue bids. Why a close second instead of tie with number 1? Oh, I don't suppose I could defend that long. But I just feel keeping the same length as dummy should be a top priority unless you can see it won't do you any good.
Thirdly, you'll sometimes have to presume your partner can take care of one suit. A low lead tends to signify some length. True, many people play 3rd and 5th best. Still, it's often better than nothing. So if your partner leads a low diamond to start the hand, and you're looking at 4-4-4-1 distribution, declarer winning the lead and taking two or three rounds of trump, forcing you into uncomfortable discards, I'd probably start discarding diamonds if the other two side suits have some pretty good tickets and aren't headed by a 6 or 7.
Examples of this profligacy can be found on any of the numbered entries in the table above, except Number Eleven, which offers an example of a skillful and astute handling of two four-card suits.