There is no reason to preempt in fourth seat. The purpose of a preempt is to keep opponents out of the bidding or to keep them from finding a contract. If you are in fourth seat and everyone has passed, you know that opponents have 22 HCP or less and probably don't have a game, so there's no reason to bid with a sub-opening hand. To do so just invites opponents to search for a part score contract they can make.
As a result of this, a two level opening in fourth seat is available for a descriptive bid if you have an opening hand. I use it to show 12+ points with a six card suit. So if I have 12+ points with a five card or less suit, I just open at the one level. But if I have a six card suit with an opening hand or better, I open at the two level. This has two positive effects:
1. It more adequately describes your hand to partner and allows you to proceed bidding without having to rebid your suit to show six cards; and
2. It hinders opponents from entering the bidding to find any contract they might have because the level is just too high to start exploratory bidding.
With that as a preamble, here's a hand we held recently:
My partner played our system and opened 2D, although I must say that it's puzzling why North did not preempt with 2 Spades in third seat, but that was the subject of my last column; when your opponents make a mistake, take advantage of it, and we did. There is a feeling that you should not preempt if you have an outside four card major. But in this situation, North, in third seat, must preempt with 2 Spades, holding six Spades and three of the top five honors. He should forget his four little hearts, especially in third seat. If North preempts with 2S, it would make our finding 3NT extremely difficult, if not impossible.
I felt my partner probably had a pretty good hand, 15-16 HCP; I had no reason for that other than instinct. I did know that she had an opening hand with six diamonds, so I immediately thought we had a shot at 3NT since I had three diamonds to an honor. My Heart bid showed a good five card suit. Since I already knew she had at least six diamonds, she was free to bid 3 Clubs to show a Club stopper. That's all I wanted to know. When she had my unstopped suit, I bid 3NT, expecting a Spade lead into my King doubleton.
Alas, my partner started thinking, never a good sign. Finally she pulled out the five diamond card, turning a cold top into an average minus. Whenever something like this happens, I know it's going to be disastrous in terms of competition, and it was. If we play 3NT we get the cold top and win. As it was, we finished a close second.
If you want a good partnership, you must trust your partner. I know her hand and I bid 3NT, which tells her that I have a stopper in Spades, the unbid suit. By bidding 3C, she's telling me she has a stopper in Clubs and is inviting me to bid 3NT if I have a stopper in Spades. After inviting the 3NT bid, she cannot then second guess me. On top of that, she had eight diamonds, not six! She knew, or should know, I had three to an honor, so she knew we had eight cold tricks just in diamonds. She had the AK of Clubs. I bid Hearts and told her I had Spades stopped. There is no reason in the world for her to override my judgment and pull it to five diamonds. She must trust me. She started out fine by bidding 2 diamonds and then telling me about her Club stopper. Why bid Clubs if she's not understanding my search for 3NT? Up until then, she was perfect. But then she chickened out, fearful of her Heart void, even though I bid Hearts and she knew Hearts would not be a problem.
Her bid is injurious for another reason. I have Spades stopped only if the lead comes from my LHO. If she's playing the hand, a Spade lead, which is what she got, means that she will lose two Spades right off the bat, since a lead through my King doubleton is a killer. To avoid losing two Spades, I must be playing the hand with the opening lead coming from my LHO into my King doubleton.
Her bid is injurious for another reason. I have Spades stopped only if the lead comes from my LHO. If she's playing the hand, a Spade lead, which is what she got, means that she will lose two Spades right off the bat, since a lead through my King doubleton is a killer. To avoid losing two Spades, I must be playing the hand with the opening lead coming from my LHO into my King doubleton.
The only way 3NT played by me can be beaten here is if North, my LHO, leads a Heart and South takes it with her Ace and switches to the Queen of Spades. Then they will take the first seven tricks. Given North's hand, however, that is extremely unlikely. A Spade switch is also unlikely since North never bid Spades and South would be looking at a Heart void on the board. So a Heart lead would be heroic and so would a Spade switch. In this hand, North has a clear lead of the Jack of Spades, especially since I bid Hearts.
But let's get back to trusting your partner. There is really no upside to doing what my partner did. What if she were right? OK, she was right. But what if she is wrong, which she was? Then there are two extremely deleterious results:
1. A very poor result, greatly affecting your competitive position in the game; and, worse,
2. A very upset partner.
Of those two, number 2 is far worse than number 1. Not only will partner be upset, but it will affect his confidence in you for the foreseeable future.
Think, also, about this. If you pass and trust your partner and partner is wrong, your partner cannot be upset with you. You will have the righteous path. So from just selfish point of view you are far better passing than making a unilateral bid that could result in the righteous fury of someone with whom you want to continue playing. Isn't it better to trust partner than to risk being wrong with all the downsides that entails? I think so.
Here, she had already described her hand to me. If her response to my 2H bid was to just rebid her diamonds, I'll either pass or bid four Diamonds (probably pass since she hasn't shown anything extra). But when she bid 3C, showing extras and interest in playing 3NT and then I bid 3NT, she can't override my judgment because I know more about her hand than she knows about mine. When I bid 3NT I should be promising three diamonds and a Spade stopper, which is what I had.
Everybody else was in either 5D or 6D (one pair, doubled, down 2), except the people who barely beat us out to be first overall; they were in 3D making six (the only way that could happen is if South leads her Ace of Hearts, which East can ruff and sluff her two spades on the KQ of Hearts, losing only a Club; never lead an Ace on opening lead unless you have the King or it's a singleton). We were the only ones who found the best 3NT contract. Too bad we didn't play it.
One of President Reagan's great quotations is "Trust but verify." In bridge it's just "trust." No verification is needed.