Free Weekly Instant Tournament - October 27 - Board 4

Board 4
Both sides vulnerable

♠ 8 5  ♥ 10 8 5  ♦ A 8 4 3 2  ♣ A K J

Three passes to me. I have 14 casino points (high-card points plus spade length). A widely accepted guideline is you need 15 casino points to open in fourth seat. I think this guideline is wrong. In my experience, passing with 14 casino tends to work out badly. And, with three-plus honor tricks, 12 HCP is an under-evaluation anyway. So I open with one diamond. 

LHO passes, partner bids two clubs, and RHO passes. Since partner is a passed hand, game is remote. I see no reason to disturb two clubs. I pass, as does LHO. RHO leads the queen of hearts.

	NORTH Phillip ♠ 8 5 ♥ 10 8 5 ♦ A 8 4 3 2 ♣ A K J
	SOUTH Robot ♠ Q 9 ♥ A 7 3 ♦ Q J ♣ Q 8 7 6 3 2

West	North	East	South
Robot	Phillip	Robot	Robot
		Pass	Pass
Pass	1 ♦	Pass	2 ♣
(All pass)

I have six clubs, a heart, and a diamond. Eight tricks. If the diamond king is onside I have nine and a possibility of more if I can set up the diamonds. If the diamond king is offside, I might still make nine tricks if I can take a pitch on the diamond ace after losing the finesse.

Unfortunately, the opponents can cash all their major-suit tricks before I get a chance to pitch. The only way I can take a pitch is if I duck the opening lead and West switches. Is that possible? Maybe. He might switch to a trump, trying to stop me from ruffing the third round of spades. It's unlikely, but I don't see how ducking can cost.

I play a low heart from dummy. East plays the nine, and I discourage with the three. West continues with the deuce of hearts--eight--king--ace.

The opponents have their major-suit winners established, and there is no way they can mistime the cash-out. I'm going to need the diamond king onside to make an overtrick. 

Can I do better? Suppose I lead a diamond and West covers. I win, play a diamond back to my hand, lead a club to dummy, ruff a diamond (with the queen if East follows), and lead a second club to dummy. If diamonds were three-three, I get two pitches to make five. If not, I may (depending on how the minor suits split) be able to ruff another diamond and return to dummy with a third club for one pitch, making four. Since I may need three club entries for this to work, I can't afford to play any trumps before embarking on this plan. So I am taking a risk that diamond are five-one. But I'm willing to take that risk.

I'd prefer West didn't cover, so I lead the diamond jack. He covers anyway. That probably means he has king doubleton. I take dummy's ace as East follows with the seven.

I play a diamond to my queen. East follows with the six; West, with the nine.

Now a club--ten--ace--five, reaching this position:

	NORTH Phillip ♠ 8 5 ♥ 10 ♦ 8 4 3 ♣ K J
	SOUTH Robot ♠ Q 9 ♥ 7 ♦ -- ♣ Q 8 7 6 3

I play a third diamond and ruff with the queen. West pitches the six of spades. Now another club to dummy. West pitches the spade three. So this is going to work. East has both the long diamond and the last club. I claim making four.

	NORTH Phillip ♠ 8 5 ♥ 10 8 5 ♦ A 8 4 3 2 ♣ A K J
WEST Robot ♠ K 10 6 4 3 2 ♥ Q J 6 2 ♦ K 9 ♣ 10		EAST Robot ♠ A J 7 ♥ K 9 4 ♦ 10 7 6 5 ♣ 9 5 4
	SOUTH Robot ♠ Q 9 ♥ A 7 3 ♦ Q J ♣ Q 8 7 6 3 2

Plus 130 is worth 82%. I'm not surprised. As I've observed before, any time you must delay drawing trump, you get a good board in this field.

I did make a mistake, however. After I ducked the heart, West can hold me to nine tricks by switching to a trump, forcing me to use one of my trump entries before I'm ready. It's ironic that I ducked hoping he would switch to a trump when in fact that's the winning defense. I was so focused on trying to make an overtrick if the diamond finesse was off that I didn't consider what would happen if the finesse worked.

It's not clear whether I made the wrong play or not. But I certainly made a mistake in not recognizing the danger of ducking trick one. So let's reconsider my decision.

Ducking the heart ace is right if the diamond king is offside and the opponents misdefend. Winning the heart ace is right if I the diamond king is onside and I can use three dummy entries and West is up to finding the club switch. Both of those are parlays and both parlays depend on the caliber of the opponents. So it's a hard question to answer.

Perhaps we can make the question easier by reframing it. If West is going to continue hearts, it makes no difference whether I duck or not. So let's assume I duck and West shifts to a club. Am I happy?

If the diamond king is offside, I'm happy. If it's onside, I don't know yet. If diamonds are three-three, my duck didn't cost. If diamonds are four-two and I can't manage a second ruff, my duck didn't cost. So I'll be happy half the time and unhappy something less than half. That suggests I was right to duck.

That assumes, of course, that there is little correlation between the fact that West chooses to shift to a club and the fact that it's the right play. In other words, I'm assuming that the club shift itself doesn't significantly change the odds of who has the diamond king. 

Is that a valid assumption? It's not clear. There are few defenders who would find a club shift for the right reason. But there are probably few defenders who would find a club shift for any reason, even a bad one. So perhaps it's a mistake to give West the chance.

I'm just as happy none of this occurred to me at the time. I might still be sitting here deciding what to do.

Free Weekly Instant Tournament - October 20 - Board 3

Board 3
Opponents vulnerable

I never know what to answer when people ask me if I open light.

Once, I opened a hand where my counterpart at the other table passed, then responded one diamond, negative, to his partner's strong club opening.

On another occasion, playing against Betty Ann Kennedy and Carol Sanders, the auction proceeded one-club (natural)--pass--pass to me. I passed, and, when Carol laid down the dummy, my partner commented that I would have opened one spade with that hand. (For the record, four spades was cold, and we defeated one club.)

One might consider those openings light. Still, if I tell my opponents I open light, then pass with this hand:

♠ K 5  ♥ A Q 5 4 2  ♦ J 6  ♣ J 9 5 2

I suspect they will feel they had been lied to. But flat hands with scattered high cards and little playing strength aren't the ones that tempt me. This isn't a light opening in my view; it's a sub-par opening.

I know most of the field will see 11 HCP and open one heart, especially in a robot tournament, where players are loathe to risk a pass-out. But I have my standards. I pass.

LHO opens with two spades, weak, and partner bids three diamonds.

Normally I would bid three hearts or three notrump. Three hearts is probably better opposite a reliable partner, who will punt with three spades if he can't raise hearts. Three notrump may be a more practical choice with a robot. But these aren't normal circumstances. This is a "best-hand' tournament, which means partner is limited to 11 HCP. Under those conditions, it's unlikely any game is good, so I pass, and we buy it in three diamonds.

RHO leads the ten of spades.

	NORTH Phillip ♠ K 5 ♥ A Q 5 4 2 ♦ J 6 ♣ J 9 5 2
	SOUTH Robot ♠ J 8 6 3 ♥ K 8 6 ♦ A K 9 4 3 ♣ 10

West	North	East	South
Robot	Phillip	Robot	Robot
	Pass	2 ♠	3 ♦
(All pass)

I'm not sure if I'm happy with this development or not. Since most will open my hand, the field will be in four hearts. It's not clear whether that will make.

I play a low spade from dummy, East wins with the queen, and I drop the six. East continues with the ace of spades. I play the three, and West pitches the three of hearts. West wouldn't be pitching from four hearts, so that means hearts are breaking, which is disappointing. The robots almost invariably pitch count cards, so West probably has three hearts. 1-3-4-5 is his likeliest shape. If that's what he has, I must lose two diamonds and a club for down one. To make, I need for diamonds to be three-three, giving West 1-3-3-6.

East cashes the club ace. That's an awfully good hand for a weak two-bid. Ace-queen sixth and an ace? That's the kind of "light" opening I like. I would have opened one spade, not two. In any event, West must have all the remaining high cards.

East continues with the four of clubs. I ruff, and West follows with the seven.

If trumps are three-three, I can play three rounds of trumps and claim. If diamonds don't break, however, West will draw my trumps and cash his clubs for down four. That doesn't rate to be a good result.

Should I go all out to make it? I'm not competing with anyone who makes four hearts. The only tables I care about are those going down. If hold three diamonds to down one, I'll tie them. If I try to make three diamonds, I'll gain half a matchpoint against those pairs if I succeed and lose half a matchpoint if I don't. So it's a 50-50 proposition. I should try to make this only if I think I have at least a 50% shot. West is a priori more likely to be 1-3-4-5 than to be 1-3-3-6. And nothing that has happened to change those odds. So my percentage play is to cash my top trumps and run winners, conceding two trump tricks.

I do need to a ruff my spade loser spade first, though. I lead the spade eight. West pitches the nine of hearts, and I ruff in dummy. I cash the ace and king of diamonds. East plays seven-five; West plays deuce-eight. I can still try to make this by playing another diamond, but I see no reason to change my mind. I run winners, conceding down one.

	NORTH Phillip ♠ K 5 ♥ A Q 5 4 2 ♦ J 6 ♣ J 9 5 2
WEST Robot ♠ 10 ♥ J 9 3 ♦ Q 10 8 2 ♣ K Q 8 7 3		EAST Robot ♠ A Q 9 7 4 2 ♥ 10 7 ♦ 7 5 ♣ A 6 4
	SOUTH Robot ♠ J 8 6 3 ♥ K 8 6 ♦ A K 9 4 3 ♣ 10

Minus 50 is worth 75%. As expected, most of the field was in four hearts. No one made it, and some managed to go down more than one.

Free Weekly Instant Tournament - October 13 - Board 2

Board 2
Our side vulnerable

♠ K Q 6 3  ♥ A 8 7  ♦ K 10 4  ♣ A K 8

RHO passes. I bid one club and partner responds with one heart. I rebid two notrump, showing 18 to 19 HCP balanced, and partner raises to three. LHO leads the deuce of spades.

	NORTH Robot ♠ 10 9 7 ♥ J 10 6 3 ♦ A Q J 6 5 ♣ 10
	SOUTH Phillip ♠ K Q 6 3 ♥ A 8 7 ♦ K 10 4 ♣ A K 8

West	North	East	South
Robot	Robot	Robot	Phillip
		Pass	1 ♣
Pass	1 ♥	Pass	2 NT
Pass	3 NT	(All pass)

West appears to have three or four spades. What should I play from dummy at trick one? 

A lead from ace-jack third would be unusual, so I'll assume West doesn't have that. I'll also assume East will play the ace if he has it, rendering my choice at trick one immaterial. (If I decide to play the seven and East finds the eight from ace-eight third, I'll start holding my cards back.)

Under those assumptions, these are the only layouts I can think of where my play matters:

(A) ♠ AJxx	♠ 8x
(B) ♠ A8xx	♠ Jx
(C) ♠ Axxx	♠ J8
(D) ♠ Axx	♠ J8x

In (A), playing the ten gives me two spade tricks. I can take two spade tricks by playing the seven also, but I would have to lose a trick to the spade jack, and I would prefer not to do that.

In the remaining cases, I can take three spade tricks if I do the right thing. In (B), playing the ten works provided I finesse the seven on the next round, whereas playing the seven always works. In (C) and (D), playing the ten works provided I don't finesse the seven on the next round. Playing the seven again always works.

In summary: (1) playing the ten, intending to finesse the seven, works for (A) and (B) (six cases); (2) playing the ten and not finessing the seven works for (A) and (C) (four cases); and (3) playing the seven immediately works for (B), (C), and (D) (seven cases). A priori, then, the seven is the percentage play.

This assumes, however, that all these cases are equally likely, that West is just as likely to lead a spade from ace-jack fourth as from ace third. For a human, that's hardly true. He is more likely to lead from ace-jack fourth. So against a human, the ten might be a better choice.

Against that, the gain in playing the ten is uncertain. Against (A), I can always take two and only spade tricks. Playing the ten gains a tempo, not a trick. It's not clear at this point whether that tempo is meaningful.

Against a human, I'm not sure what I would do. But against a robot, who likes short-suit leads, I think the seven is probably better.

I play the seven, and East wins with the ace. So all this analysis was moot. I now have five diamond tricks, a heart, two clubs, and two spades. Ten tricks ready to cash. If I have three spade tricks, I have eleven.

At trick two, West shifts to the club queen. If the shift is from queen-jack-nine, I might be able to catch East in a club-heart squeeze for an eleventh trick. To set up the squeeze, I will have to duck a trick to correct the count, and I will have to isolate the heart guard in East's hand. If the heart honors are split, I can do both of these things by crossing to dummy and leading the heart jack. East can't afford to cover, so I will duck the trick to West. If West defends passively, I can run my winners, coming down to this position:

	NORTH Robot ♠ -- ♥ 10 6 ♦ 5 ♣ --
	SOUTH Phillip ♠ -- ♥ A 8 ♦ -- ♣ 8

The last diamond squeezes East in hearts and clubs. West can break up the squeeze by continuing hearts. But if he has the heart nine, he can't do that.

I win the club shift with the ace; (The king clarifies the position for East.) West follows with the three. I might as well cash a spade to see if the jack drops. If it doesn't, testing for three-three spades will have to wait until after I duck the heart.

Actually, there is another reason to cash a spade. If West has jack-eight fourth, cashing a spade allows him to return the spade jack after winning his heart trick. The prospect of setting up his spade eight may make a spade continuation appealing and may prevent him from finding the heart continuation to break up the squeeze.

I cash the spade king. East follows with the eight. Too bad. Now West doesn't have a safe spade exit.

To lead the heart jack from dummy, I'll need to take the slight risk that diamonds are five-zero. I lead a low diamond to dummy's jack. Fortunately, both opponents follow. Now the heart jack--four--seven--queen.

West doesn't find a heart continuation. In fact, he leads away from his spade jack, giving my my eleventh trick in the spade suit. I claim the balance. Making five.

	NORTH Robot ♠ 10 9 7 ♥ J 10 6 3 ♦ A Q J 6 5 ♣ 10
WEST Robot ♠ J 5 4 2 ♥ Q 9 2 ♦ 9 3 2 ♣ 5 4 3		EAST Robot ♠ A 8 ♥ K 5 4 ♦ 8 7 ♣ Q J 9 7 6 2
	SOUTH Phillip ♠ K Q 6 3 ♥ A 8 7 ♦ K 10 4 ♣ A K 8

Plus 660 is worth 96%. The spade shift at the end made it easy, but there was nothing the opponents could do. East was going to be squeezed anyway.

Most declarers ran diamonds right away, destroying the possibility of a squeeze. Sometimes it's a good idea to run your winners early, forcing  the opponents to discard before they know what's going on. Sometimes that's true even it means giving up on a legitimate chance, provided that chance is small. 

I don't think that's the case here, however. The squeeze isn't all that unlikely. And it's hard to see what mistake the opponents will make if you run diamonds early. 

Free Weekly Instant Tournament - October 6 - Board 1

Board 1
Neither vulnerable

♠ 9 4 3  ♥ A K Q 6 4 2  ♦ A 6 2  ♣ A

Two passes to me. I open with one heart, LHO passes, and partner raises to two hearts. I'm worth driving to game, but it's not clear which game to drive to. I have eight tricks off the top, so one trick in partner's hand, assuming it's fast enough, is all I need for three notrump. Finding ten tricks in hearts may be harder. 

At IMPs, I would certainly bid three notrump, since it rates to be the safer game. But at matchpoints, the prospect of a spade or diamond ruff in dummy tempts me to try four hearts.

Players often get this backwards, spurning a major to play three notrump at matchpoints but not at IMPs. At matchpoints, it's better to play the major if it takes only one trick more than notrump. At IMPs, the major must take two tricks more (ten versus eight) before the major is better. So, in general, you should choose the major more often at matchpoints than at IMPs.

I bid four hearts, everyone passes, and LHO leads the seven of hearts.

	NORTH Robot ♠ Q 6 5 ♥ J 9 8 ♦ K 8 7 ♣ J 10 9 8
	SOUTH Phillip ♠ 9 4 3 ♥ A K Q 6 4 2 ♦ A 6 2 ♣ A

West	North	East	South
Robot	Robot	Robot	Phillip
	Pass	Pass	1 ♥
Pass	2 ♥	Pass	4 ♥
(All pass)

Three notrump is clearly the right spot at IMPs. Unless the opponents can take five spade tricks off the top, three notrump is cold, and four hearts is tenuous. It's not clear what the right spot at matchpoints is.

It's unlikely West led a trump holding the ace-king of spades, so I will need to find my tenth trick in the club suit. I can take two ruffing finesses, but I need three dummy entries to do so. This means I need to reach dummy twice in hearts. Does that work? I can unblock the club ace, lead a heart to dummy, and lead the jack of clubs, ruffing if East covers and pitching a spade if he doesn't. Then another heart to dummy for the second club finesse. Finally, I return to dummy with the diamond king to take my pitch.

Yes, it works, assuming East has at least one club honor. The question is, do I have two trump entries? If I play low on this trick and RHO covers with the ten, then yes, I do. If the ten does not appear, I will need to decide whether to play for two-two hearts or to finesse West for the ten.

I play the heart eight. East covers with the ten. Problem solved.

I win in my hand with the king, cash the club ace--four--eight--deuce and play the deuce of hearts to dummy. West pitches the diamond four. So East made an error in covering. I would go down had he withheld the ten.

I lead the club nine. East covers with the queen, and I ruff. West follows with the six.

I lead another heart to dummy, lead the club ten, pitching a spade, and lose the trick to West's king. Eventually I pitch my diamond loser on the good club. Making four.

	NORTH Robot ♠ Q 6 5 ♥ J 9 8 ♦ K 8 7 ♣ J 10 9 8
WEST Robot ♠ A 8 2 ♥ 7 ♦ Q J 4 3 ♣ K 7 6 5 4		EAST Robot ♠ K J 10 7 ♥ 10 5 3 ♦ 10 9 5 ♣ Q 3 2
	SOUTH Phillip ♠ 9 4 3 ♥ A K Q 6 4 2 ♦ A 6 2 ♣ A

Plus 420 is worth 93%. No one was in three notrump. Most of the field was in four hearts going down. As I've observed before, the field in these Instant Tournaments is terrified of not drawing trump. Any time you must delay drawing trump, you get a ridiculously good result.

East could defeat this contract by playing a low heart at trick one. This is the kind of play a human is more likely to find than a robot. Robots decide what to do by generating random deals. If a robot doesn't happen to come across a deal where a particular play matters, it has no reason to find that play. 

Humans, on the other hand, can sometimes follow general principles without needing to construct a full deal. That's not always a good idea. Sometimes general principles fail. But here this approach works just fine. You can see that if you play low, you deprive declarer of a late dummy entry. That's often a good idea even if you can't see how it might help. So playing low should be routine for an expert human.

Robots would play better if they started with their deal-generating approach, then followed general principles if they thought their play didn't matter. But where should these general principles come from? A few years ago, the state of the art required deriving rules by interviewing human experts. This was always an unreliable process, since experts have often internalized their expertise and aren't consciously aware of why they do things. Now, with the advancements in generative AI, the technology exists to allow robots to generate their own rules. Using this approach, I suspect they will find rules we aren't even aware of. If anyone succeeds in doing this, we will see an astonishing improvement in how robots play.

Postscript:

In the above write-up, I stated "I'm worth driving to game" without comment, since I didn't think that would be open to question. But when I posted the hand to the Bridge People group on Facebook, the majority of respondents simply made a game try. So I suppose I should justify my statement.

The lazy way to decide what the hand is worth is simply to count points. You have 19 total points: 17 HCP plus one for the fifth heart and one for the sixth. Marshall Miles, in How to Win at Duplicate Bridge, suggested that, when partner raises your suit, you should add two points for holding six cards in your suit, two more for holding seven, one for a side singleton, and two for a side void. I've found this method of valuation to be quite accurate. Under this method, the hand is worth three additional points, bringing the total to 22. One normally makes a game try with 17 or 18 and drives to game with 19. So 22 is more than enough to bid game.

A more accurate way to decide what the hand is worth is to give partner a perfect minimum, say, two kings, three trumps, and a useful doubleton. If that gives you a virtually laydown game, then you should invite. If partner accepts with a maximum, perhaps the perfect minimum with be included in that maximum. If not, then perhaps game won't be cold but will still have decent chances. With this hand, all you need for game is  king doubleton of diamonds. That's a full king less than a game try by this method, so the hand is worth driving to game.

Free Weekly Instant Tournament - September 29 - Board 8

Board 8
Neither side vulnerable

♠ A K Q  ♥ K 9 6 2  ♦ Q J 8  ♣ K 9 7

Three passes to me. I have a balanced hand with 18 HCP, so I open with one club, planning on rebidding two notrump to show 18 or 19. LHO and partner pass, and RHO balances with a double.

I can now show my 18 to 19 HCP by bidding one notrump. The problem with that call is that LHO might well have a good hand with a club stack. If so, he is well placed to double me. Redoubling might be safer than bidding one notrump. It gets my values across, allowing partner to compete with a long suit. And if partner is broke, we can perhaps find a playable spot at the one-level.

Unfortunately, I haven't had much success engaging robots in complicated auctions. Even with my regular partners, I'm not sure what redouble should mean here. In particular, I'm not sure how prepared I should be to play in one club redoubled if LHO passes. So I'm not about to throw this auction at a robot. If I bid one notrump, at least there is no doubt in partner's mind what I have. (If anyone has a firm agreement about what this redouble shows, please comment.)

I bid one notrump. Everyone passes, and LHO leads the three of hearts.

	NORTH Robot ♠ 7 6 4 3 ♥ Q 8 5 ♦ 9 4 ♣ J 10 6 5
	SOUTH Phillip ♠ A K Q ♥ K 9 6 2 ♦ Q J 8 ♣ K 9 7

West	North	East	South
Robot	Robot	Robot	Phillip
Pass	Pass	Pass	1 ♣
Pass	Pass	Double	1 NT
(All pass)

Given the small heart lead and East's take-out double, hearts should be three-three. If West has led from jack third or ten third (or even ace third if I guess it), I have three heart tricks. Three spade tricks brings me up to six. LHO probably would have led a diamond with ace-king, so I should have a diamond trick. If the opponents give me the tempi, I may manage one or two club tricks as well.

I start by playing a low heart from dummy. East plays the jack, and I win with the king. The robots sometimes falsecard from equals in the middle of the hand, but I've never seen them do that at trick one. So I'm fairly confident the heart ten is onside.

I might as well set up my heart tricks. I'll have one heart entry to dummy. If I catch RHO with a doubleton club queen, I can set up two club tricks. Or I could play him for the ace and settle for one.

I play the deuce of hearts--ten--queen--ace. The ten? I suppose he was unblocking in case his partner had ace-nine fourth and I had made a curious play.

East shifts to the diamond deuce. Is the jack or queen most likely to induce West to shift after winning this trick? Perhaps if I play the jack, West will place me with AJ10 or KJ!0 and not wish to finesse his partner's queen. I play the jack, West wins with the king, and I unblock dummy's nine, trying to represent a good diamond holding in my hand.

I can't say whether my diamond plays worked or whether West was going to shift anyway. But, for whatever reason, West shifts to the heart four. I win in dummy as East follows with the seven.

East has the ace-jack of hearts and presumably the diamond ace. As a passed hand, he can't have the club ace, but he might have the queen. I lead the club five from dummy--four--nine--queen. West shifts to the nine of spades--three--deuce--queen. If I lead the club king, I assume West will duck it, preventing me from taking two club tricks. But at least I'll have my seventh trick.

I might as well cash my heart first and force discards. On the heart nine, West pitches the club three. I pitch dummy's diamond, and East pitches the club deuce. It appears East was either 4-3-4-2 or 3-3-5-2.

I lead the club king. West, of course, ducks, and East pitches the diamond six. I've made my contract. If I can guess the layout, I can take an overtrick. Here are the two possibilities.

(A)

	NORTH Robot ♠ 7 6 4 ♥ -- ♦ -- ♣ J 10
WEST Robot ♠ x ♥ -- ♦ x x x ♣ A		EAST Robot ♠ x x x ♥ -- ♦ A x ♣ --
	SOUTH Phillip ♠ A K ♥ -- ♦ Q 8 ♣ 7

(B)

	NORTH Robot ♠ 7 6 4 ♥ -- ♦ -- ♣ J 10
WEST Robot ♠ x x ♥ -- ♦ x x ♣ A		EAST Robot ♠ x x ♥ -- ♦ A x x ♣ --
	SOUTH Phillip ♠ A K ♥ -- ♦ Q 8 ♣ 7

In (A), I must cash one spade, depriving West of his exit, then lead a club. West must then lead a diamond up to my ace. If I make a mistake and cash two spades, East will have a spade to cash when he wins the diamond ace.

In (B), I must cash both spades before tossing West in. If I cash only one spade, he will have a spade to exit with, forcing me to lead diamonds out of my hand.

In any event, I must cash at least one spade. I cash the ace--eight--four--five. Now what? Which layout is more likely, (A) or (B)?

Perhaps with four diamonds West would have been more inclined to continue the suit after winning the king. In fact, maybe he would have bid two diamonds over one notrump with four of them. I don't know if he would or wouldn't. But at least he would have the option. With 3-3-3-4, he has no suit to bid. 

Neither inference is especially compelling, but at least they both suggest (B). I can't think of any other clues.

I cash the spade king. Everyone follows. I exit with a club and score my diamond queen in the end. Making two

	NORTH Robot ♠ 7 6 4 3 ♥ Q 8 5 ♦ 9 4 ♣ J 10 6 5
WEST Robot ♠ J 9 8 ♥ 10 4 3 ♦ K 7 3 ♣ A Q 8 3		EAST Robot ♠ 10 5 2 ♥ A J 7 ♦ A 10 6 5 2 ♣ 4 2
	SOUTH Phillip ♠ A K Q ♥ K 9 6 2 ♦ Q J 8 ♣ K 9 7

Plus 120 is worth 100%. The overtrick made little difference. Even making one would have been worth 96%.

It's not my declarer play that made the difference, however. Weirdly, almost everyone is opening one notrump with this hand. I have no idea why. But against one notrump--all pass, West chooses to lead a diamond, which beats the contract.

That's also weird. I would do exactly the opposite. After one notrump-- all pass, one leans toward leading a major, since dummy won't have five cards in the major but partner might. But on the auction we had, partner is unlikely to have a five-card major, since he chose to double rather than overcall. If he has a five-card suit, it's probably diamonds. So I would choose a diamond on our auction but not after one notrump-all pass.