In the semifinals of the open trials, you have to decide just how to handle a strong hand in competition.
N-S vul, South deals. As South, you hold:
1♣: 16+ points; 1♦: 0-8 points; 1NT: Minors
Your agreements are along unusual over unusual lines.
Pass: Nothing particular to say
Double: Interest in penalizing them, ability to double at least one of their suits
2♣/2♦: Good hand in hearts/spades respectively
2♥/2♠: Minimal hand in that major
3♥/3♠: Natural game force
Even though you have a strong diamond holding, you aren't going to want to defend 2 of a minor doubled. You have a strong heart suit, and that suit must be shown. It is better to go after your own contract than to go for a marginal penalty.
The question is how strong a hand to show. This hand certainly isn't worth forcing to game. On the other hand, it is stronger than you might have for a 1♣ opening with a heart suit. 2♣ shows this quite well. If you bid 2♥, you may miss a game, as partner won't play you for this strong a hand.
You choose to bid 2♥, ending the auction.
West leads the ♣9.
East wins the ♣A. At trick 2, East returns the ♥8 to dummy's ♥10.
What will you be leading for trick 3?
Clearly you will leading a diamond off dummy. You will need to develop one diamond trick to make your contract. Since there is no urgency about drawing a second round of trumps and you may wish to make two diamond plays from dummy, you might as well make the first diamond play right now.
It isn't immediately obvious just what you will be doing in the diamond suit. In any event, it can't hurt you to lead the ♦8. Leaving the ♦87 in dummy can't be of value. Perhaps you will let the ♦8 ride, but you don't have to make that decision right now. Perhaps East will cover with something which may make things easier. Or perhaps you may get a read from East about his diamond holding when you lead the ♦8.
If East plays the ♦2 on the ♦8 and you don't get any kind of read, what will you do?
You know quite a lot about this hand. East is at least 5-4 in the minors. West probably doesn't have a singleton diamond or he would have led it, so East should have 5 clubs and 4 diamonds. If West had a 6-card spade suit he probably would have bid some spades over the 1♣ opening. So, you can assume that West's shape is 5-4-2-2 and East's shape is 3-1-4-5.
The diamond suit presents an unusual combination. You probably have never analyzed this exact position before. So you have to re-invent the wheel and start from scratch.
For starters, from East's point of view, the ♦6 could be a meaningful spot card. While it could conceivably be right for him to play the ♦6 from some holding including the ♦2 for deceptive purposes, in practice, no player is going to think of anything like that. Thus, there is no restricted choice on the small spots involved, which makes the remaining combinations equally likely if there are no other considerations.
West has 10 possible doubletons. They are AQ, AJ, A9, A6, QJ, Q9, Q6, J9, J6, and 96. The only one we can rule out is QJ, since with that he would have led a diamond instead of a club. We can also rule out half of 96 doubleton, since with that he would have had equal holdings in the minors and would have led a diamond half the time.
If you play the ♦K, you lose to the four ace-doubletons, and win on the other doubletons. That is easy.
If you play the ♦10, you lose immediately to Q6 and J6 doubleton, since the defense can then take a ruffing finesse through your king. You win against A9, A6, and 96. On the other holdings, you will have to guess on the second round. If you guess to go up king, you will lose to AQ and AJ. If you guess to duck, you will lose to Q9 and J9.
If you let the ♦8 ride, you lose to 96 since they get a ruffing finesse. Should the ♦8 lose to the ♦9, the percentage play on the second round will be low to the king, losing only to A9 doubleton. If the ♦8 drives out the ♦J you can ride the ♦7 next round (covering the ♦9 with the ♦10) and always make, except for QJ doubleton which is very unlikely. It is true that in theory West could falsecard with an honor from J9 or Q9 doubleton, but in practice there isn't 1 player in 100 who would work out to make that play. In addition, if East has ♦AQJ2 he might not duck, as that would be very bad for him if you started with ♦K10x and put in the ♦10. So, riding the ♦8 is definitely the percentage play.
If East plays the ♦6 under the ♦8 and you don't get any kind of read, what will you do?
If you make the reasonable assumption that East would never play the ♦6 if he has the ♦2, the only four combinations with West are A2, Q2, J2, and 92.
Playing the king loses to A2. Playing the 10 loses to Q2 and J2, so that is clearly wrong. Playing small loses to 92. Once again, 92 is a priori half as likely as the others, since with that, West might have chosen a diamond lead. Also, once again East might not have ducked with ♦AQJ6 for fear you have ♦K10x.
Against that, if East started with ♦QJ96 he would know he has all the spots, and might be afraid you would led the ♦8 ride if he ducked. So, he might play the ♦9 or an honor from that holding. If you believe that possibility outweighs everything else, then you should go up ♦K when you see the ♦6. Otherwise, you should make the percentage play of letting the ♦8 ride.
If East covers the ♦8 with the ♦9 and you don't get any kind of read, what will you do?
This one is easy, Cover the ♦9 with the ♦10. If that loses to the ♦J, go back and ride the ♦7. If that isn't covered, you are home. If it goes queen, king, ace, you can later power out the ♦6 (with the ♦5 to make it look pretty, of course) so your 3-spot can win the fourth round of the suit.
If West happens to shift to a spade (not that he would ever find that in practice), you would duck the first round of spades so East could not get in at the wrong time to give West a diamond ruff.
You lead the ♦8, planning on letting it ride. However, East has a clear problem on this trick. After some thought, he plays the ♦2. Does this change your plans?
You can be sure that East isn't coffee-housing you. He has a real problem, or at least in his mind he has a problem. It is your job to determine what that problem is.
In some cases when a player has a problem, it is because he is trying to determine whether or not to go up with an ace. That isn't the case here. East knows that you don't have a singleton king. From most holdings including the ace, he will have no difficulty playing small, particularly if he doesn't have the ♦9. He might be considering whether to cover from something like ♦AJ9x, but that doesn't look likely.
The one holding where East might have a problem with the ace is if he holds ♦AQJ2. Now he has to worry about the possibility of you holding ♦K10x. If you believe that is his problem, you should go against the odds and play the king. However, while this position does present a potential real problem, in practice I think most defenders would just go one way or the other pretty quickly, for fear that if they thought a long time and played small they would be giving the position away.
A more likely holding for East's problem is ♦Q962 or ♦J962. The card combination is probably as unfamiliar to him as it is to you. He will be worried that you have some 4-card holding where it is technically necessary for him to cover the ♦8. One can just see his mind spinning, trying to sort through all the various possibilities in a few seconds, since he fears that if he takes too long you will know from the huddle what he has. That argues for making the same play you would have made without the huddle -- riding the ♦8.
There is one other point involved. Suppose you ride the ♦8 and it loses to the ♦9. A good case could be made for playing West for ♦A9 doubleton, which was not your original plan. The reason is that an expert East wouldn't have a real problem on the ♦8 if he held ♦AQ62 or ♦AJ62, but if he held ♦QJ62 he might be concerned that it could be necessary to cover the ♦8. If you trust your read, you may well make this anti-percentage play, although be prepared to apologize if your read is wrong and West does have ♦Q9 or ♦J9 doubleton.
You choose to go up king. You are wrong. West wins the ace. The defense makes no mistakes, and you are down 1. The full hand is:
East was working out whether or not his spots justified covering the ♦8. He worked out correctly that they do not, but that should have tipped declarer off about the diamond position.
It is nice to have a bunch of card combinations memorized so you don't have to figure them out at the table. Occasionally, however, an unusual combination such as this one will present itself, and you need to go back to basics in order to work out the percentage play.
The question of whether one should alter ones play based on a read of an opponent is always a difficult one. Some players just stick to what they know is the percentage play, unwilling to trust their table feel. However, bridge players are human, and human beings do give away information. The difficult part is knowing how to interpret that information.
Plus... it's free!