Tuesday, December 31, 2019

Examples of doubling: good and bad

Starting with the bad. This hand was discussed on BridgeWinners. You hold K862 KQ4 QJ963 7 as dealer, all white, IMPs. Playing Precision, you open 1 and partner responds 1. RHO now doubles and you redouble to show three cards in hearts. LHO bids 2 ♣ and this is passed around to you.

Are you thinking of doubling?  I believe that there are three reasons that you should not double here:
  • You have a minimum hand; partner has shown a minimum response (theoretically, you should only respond to 1 with 8 hcp but that's very old fashioned so, let's assume partner has at least 6 points). This is not necessarily your hand so making a cooperative double here puts partner under a lot of pressure.
  • You have only a singleton club; if partner chooses to pass for penalties, the opponents will be playing at the two-level with an eight-card fit--that's anti-law.
  • You have a seven-card heart fit since partner would have bid 2 if he had five and there's no reason to suppose that you have an eight-card diamond fit (you might but the way to find out is to bid 2 and see if partner lets you play it there).
The bottom line here is that this is the kind of hand that gets cooperative doubles a bad name. At the table, this hand doubled, partner left it in with a 9-count including KQ92 of clubs and the ace, third of spades. The contract made for -180.

OK, now let's go to the good example hand. This occurred in a daytime game today, playing with my favorite partner. Everyone is vulnerable (matchpoints) and LHO, the dealer passes. Kim bids 1 and RHO, a good "B" player, overcalls 2. Our hand is 875 KJT54 KQ9 J4. Some people might start with 2 but, in a competitive auction, I like to show support right away. I therefore bid 2. LHO and partner passed and RHO bid 3. Now, I doubled. The play was straightforward and we ended up with 500, for all the matchpoints.

So, why is this a penalty double rather than a cooperative (takeout-oriented) double? I explain this in Update on Cooperative Doubles. But, basically, I have made a limited bid (2) and partner has nothing extra because she passed. It's impossible that we have sufficient strength for a cooperative double (see the first bullet regarding the bad example above). Therefore, it must be a penalty double.

Note that RHO did nothing too outlandish. He had 16 high card points and a fairly good six-card diamond suit (missing the KQ, obviously, and the ten which his partner had along with two small). He was just unlucky that his partner had only two queens that were not much help.

Sunday, December 8, 2019

Lead-directing doubles

How good should your suit be to make a lead-directing double of an artificial bid? Let's think about what we're trying to achieve when we make one.

What we're trying to achieve is to get our defense off to a better start than partner might come up with on his own. The danger of course is that partner might have a very good lead of his own (Q from QJTxx, for example) which he will eschew in order to lead your suit. On other occasions, partner has no good lead and will be thrilled to get your suggestion, even if it turns out not to be the killer lead. At least, it will have been neutral.

So, in order to ensure that your suggested lead is at least neutral, apply this rule: can you guarantee that you will win at least one of the first two tricks of the suit?

I'm posing this question in a no-trump context. Against a suit contract, the second or even the first lead of a suit might get ruffed and you might have simply accomplished setting up a trick which can never be cashed. But you won't have lost anything.

So, what honor holdings would qualify for a lead-directing double?

  • AK? Obviously!
  • KQ? Yes: whoever has the ace you will establish one trick.
  • AQ? Yes: if dummy happens to have the K, you'll win two tricks.
  • KJT? I don't think so.
  • KJ? No, no, no!!
  • Anything else? Don't even think about it.

What's about KJT? You will build a trick with this holding even if declarer has ace and queen. But you may never get to cash it. Is it really worth risking the possibility that partner has a better lead? Maybe but, on balance, I think not.

What about accompanying length? How about making a lead-directing double of an artificial bid with AKx? What could go wrong? We almost definitely will get to cash two tricks. Maybe partner has a doubleton and can ruff the third round! There's just one little problem. The opponents, who nearly always have more high-card points than your side, might just decide to redouble!

How about AKxxx? The danger is still there (partner may have a void) but I think that you'd have to get very unlucky to find them redoubling and making. Plus, you will have some company at least.

Thursday, August 8, 2019

Thinking ahead

In a recent Daylong IMP tournament on BBO, I picked up the following hand: AKT742 AQJ62 void KT. We were vulnerable vs. not vulnerable and my robot partner dealt and opened 1. RHO bid D. What's your bid going to be?

You've got both majors, so how about a negative double? Predictably, LHO now bids 4 and when it comes back to you, you can offer a choice of majors by bidding 4. Did you land on your feet? Hardly! You can surely make slam and possibly a grand slam. How are you getting there when partner passes 4? So, you're kind of obliged to bid 6 now.

In other words, just thinking one move ahead in the auction tells you right away that double is a bad idea. Actually, it could be even worse. Suppose partner's hand is xx xxx AQx AKxxx? He might even pass 3X and you might score only 500: not even compensation for game.

I've seen some abuses of negative doubles in my time, but I think this one takes the cake. The primary purpose of a negative double is a bit like Stayman: opposite a relatively balanced opener, let's see if we can find a 4-4 fit. Opener is reluctant to bid a three-card suit opposite a negative double. How many cards in the majors do you really expect partner to have here?

At my table, I bid 3 over 3 and, after my LHO predictably raised to 4, my partner was able to raise me to 4 with his Q96 holding. Roman keycard Blackwood did the rest: I found out that we had all six key cards (including the A in case I wanted to bid 7NT) and I didn't really have to think too long and hard to bid the grand. But which grand? If it had been MPs, I would have probably bid 7NT. But at IMPs, you should maximize the chances of making by using your nine (hopefully) trumps.

Here's the whole hand:

The contract was lay-down. I scored six spades, five hearts, two clubs, a diamond ruff, and the A. I'm kidding as that adds up to 15 so I never scored a diamond or the fifth heart.

There were five others in 7 (we won 12.5 IMPs on this hand), ten in 6, ten in a spade game, and one unfortunate fellow in 7 down six. To say that he (or she) was hoist by their own petard would be an understatement: South never bid either of his majors: he began with a negative double then, after his partner doubled 4, he chose 5 (which the robots interpret as showing club support).

Monday, July 8, 2019

How to lose 50 IMPs in a 12-board Individual

Yes, you read that correctly. Sometimes when I'm feeling particularly masochistic, I enter one of the ACBL individual tournaments. The denizens of this particular enclave are all regulars. I have notes on many of the players. Of course one's result is almost entirely the luck of the draw. It's seldom that I make an error so egregious that it significantly affects my score as the standard of play is so bad that you really have to go out of your way to lose a board all on your own. So, basically my score is always a combination of my so-called partners' efforts and those of my opponents.

Today's was exceptional. Board one was uneventful. The opponents bid and made a game. Lose one IMP.  The second board was where the (un) fun started. My CHO (partner) was in 3NT:

As you can see (by pressing Next), declarer won the opening lead in dummy and proceeded to cash the CA just in case it "went away." Then they figured that since they were there for the last time, it might be a good idea to take a finesse. There was only one suit with a finessing position and that was hearts. So, despite the fact that they could ill-afford to lose the lead before setting up the diamonds, they finessed the HT. This had approximately a 25% chance of success. Partner was unlucky. From there on, there simply wasn't time to get the diamonds going. The result? Down 2 instead of making 6. But it was IMPs, so the three overtricks we didn't make were just gravy (or lack thereof).

The next, however, surpassed even this.

The funny thing is that, after the hand, CHO messaged me to say "look at the other tables to see how you should bid this hand." Some had opened the West hand (not terrible), some Norths didn't open 2D. Of the Wests where the first round of bidding was the same, some bid only 2H (but their partners still got them to game). One player bid 4H (obviously, if I'd known anything about CHO I would have done the same). But most, like me, bid 3H. No other partnership got the magic +230, nor yet 1430. That was another 10 IMPs.

The next hand was interesting. Neither I nor my CHO did anything terrible:

RHO got a bit lucky that North didn't have four clubs to the J as he might have done. If he doesn't cash his clubs out, we can easily come to 10 tricks. You can blame me for not bidding 3NT instead of 1S. But, seriously, although this rated to be a not uncommon result, it was in fact unique. Lose another 8.

I managed to staunch the flow a bit over the next three boards, for only another 7 IMPs. The third one of these offered 12 tricks to the opponents, but nobody bid the slam.

Most Wests opened the bidding with 4D, some 3D and at least one opened 1D. In every one of these cases, East bid his hearts and 4H was made. There is an argument for 1D but I think it's better to get the hand off one's chest right away. 8 IMPs.

The next board was an unmitigated disaster and I was significantly responsible for it.

Believing my partner to have no defense against 5D (he passed in a forcing pass situation), I decided to try for 5H. I took a while to decide whether to run the HT and cost us an additional 4.5 IMPs (over the 7 we were destined for) when I changed my mind and went up with the ace. Of course, most of the players in these events have no concept of a forcing pass, so it was silly to take such an inference.

Here is the final exhibit:

Watching the play as dummy, I was praying for my partner to claim before anything bad happened. My prayers went unanswered and he decided to take a practice finesse at trick 8. Lose another 9.

At this point, I was an incredible 62.5 IMPs under water on only ten boards! I did manage to get some back on the last board, but surely this is a record. I'm hoping that someone will nominate me for the Guiness Book of Records.

Sunday, June 30, 2019

A very ordinary hand

It has been said that the way to win at bridge is to make sure you get the ordinary hands right. In other words, squeezes, endplays, deceptions, coups of various sorts, etc. don't come up sufficiently often to give an advantage to the better player. But ordinary hands come up all the time.

Here's a hand from yesterday's STAC game:

I was sitting West and essentially took no part in the proceedings. Our opponents, two experts who are married (to each other) and sometimes--but not usually--play together, had the auction all to themselves. I might have opened 1C in third seat and perhaps I should have but I suspect that would have pushed them into a making 4H).

At my club, every N/S pair was in a heart part-score, mostly 2H by North but sometimes, as at our table, 3H by North and, once, 3H by South. My partner led the C4, clubs being the only safe-looking lead, although either red deuce would also be safe on this layout. Declarer ruffed out the spades, took two diamond finesses and emerged with 10 tricks pointing his way. A flat board, right?

Wrong. This was by no means a flat board. Here were the scores: 1 @ 200 (11), 6 @ 170 (7.5), 3 @ 140 (3) and 2 @110 (.5). I'll dispense with the anomalous scores of 200 and 110 and concentrate on the 170s and 140s.

At first, I couldn't see why our score was below average (3.5). We didn't put a foot wrong. How could declarer not take 10 tricks. And then I saw it: some declarers must have taken the spade finesse.

This hand of course is a perfect illustration of the (general) superiority of a 4-4 trump fit over, say, a 5-3 or 5-2 trump fit. You can usually use long cards in the long suit to discard losers from the other hand while using small trumps to ruff with, possibly ruffing out losers to establish the long suit.

But the main point here is that considering a suit, the spades in this case, in isolation may yield a different plan than considering the suit as part of a whole hand. If you were in a spade (or notrump) contract here, you would consider your play in the spade suit and opt for the 43% likelihood of the bringing in the suit with a finesse against the queen, versus the 18% chance of dropping a doubleton or singleton queen. Not even a close decision.

But here, you are in a suit contract and you have the luxury of being able to ruff a spade (we'll assume that trumps are 3-2, as here, for the sake of simplicity). The probability of dropping the queen after a ruff is: 36% for a 3-3 split, plus the same 18% chance that the queen would have dropped anyway. That's a total probability of 54%. The failure zone (46%) is made up of 32.3% for Qxxx, 12% for Qxxxx, and 1.5% for Qxxxxx.

So, again, it's not really a close decision if you know your probabilities (54% vs. 43%). Incidentally, it's a very common error to regard the finesse as a 50/50 shot. But when we can only finesse twice, as here, there will be holdings on our right that we can't pick up: half of the Qxxxx and Qxxxxx layouts we noted above, that's to say 6.75% of cases.

The conclusion is that the situation where you are missing six cards is a tricky one--and also a common one. It's worth spending some time to learn the probabilities.

Monday, June 24, 2019

Discipline vs. guessing

One thing I've noticed about experts is that they try not to guess. That doesn't mean they never guess. But they do try never to take the last guess. Is this the same thing as "discipline?"

One type of undisciplined bid is when you deliberately fudge your hand to fit a bid that you'd like to make. For example, you pick up a balanced 14 count with no special features and, just because you feel like it, or want to be declarer, you decided to open 1NT showing 15-17. Sometimes, this will work well when partner has 9 hcp and a long minor and 3NT is cold on 23 hcp. But other times, partner will invite game and the limit of the hand will be 1NT. This kind of thing is a partnership issue, and your partner will eventually become unhappy, unless your declarer play is first rate.

But there's a different kind of discipline where you are likely making the last bid for your side. Partner is probably not going to bid again, so can't really be deceived. A lot will depend on the form of scoring and the state of play, so to speak. Matchpoints vs. IMPs? Competitive situation vs. non-competitive? High-level or low-level decision? High entropy or low entropy (entropy is complementary to information)?

Here's a high-level, IMP pairs, competitive, high-entropy situation, i.e. a lot is resting on this decision:

AKJ3 KJT983 T8 9. All vulnerable.

Partner opens 1S in second seat and RHO bids 5C. That's annoying! We have no idea whether partner has a minimum or maybe is just below a 2C opener.  Well, we do have a pretty good idea that RHO has most of the high cards in clubs and we have 12 high card points. Partner can't have much more than 18 then.

Let's do some arithmetic.  What might happen if we pass? Partner will probably be passing too and we might go anywhere from +200 to +400. What about double? Assuming that partner doesn't take it out then we could score 500 to 1100. If he takes it out to 5D, we can always go back to 5S.

Can we make 5S? Assuming that we have no trump losers, we've got three losers. Surely, with his opening bid, partner can cover one of those. So, it looks like 650 is likely available to us. There might be a few pairs defending 5C, possibly doubled. Bidding 5S is probably worth about 4 to 6 IMPs over defending.

What about slam? This is where, the lack of information is really troubling. We can no longer ask for keycards so it's going to be decision time immediately.

If partner has two aces (particularly if one of them is the diamond ace--not an unreasonable expectation), we can very likely make 1430 for 13 IMPs over and above the 650 and about 14 IMPs over and above defending. In other words, just by bidding 5S we are almost locking in 5 (approx) IMPs. Bidding 6S will gain an additional 9 IMPs if it makes.

But, what if it doesn't make? We will be -100. We lose not only the 5 for grabbing the declaration but an additional 7 or 8 for going down.

To put it mathematically, we risk 13 to gain 13. An even money bet. We'd take the same bet at matchpoints.

This is how many bridge players would evaluate this choice: mentally flip a coin, likely favoring the slam decision simply because it's just more fun that way.

But the true expert will say this: "I can't find out if 6S is on, so I'll assume that it isn't and just bid 5S." A popular expression that covers this situation is "when you're fixed, stay fixed."

Wednesday, June 12, 2019

The Vienna Coup

Looking at the MITDL Bridge Club's web site recently, I was a little embarrassed to note that there's a link there to my blog claiming that it's updated every week. Those were the days! This is my first post for nine months!

Today I had the pleasure of playing with Harrison Luba a.k.a. The Twerp. He's currently a freshman in High School and is an incredible player already. Like most Juniors, he believes that all doubles are for takeout unless it's blindingly obvious that they're for penalties. Those of you who follow (or attempt to follow) my blog know that I have a set of very specific (although quite simple) rules on this. So, we had a couple of bad scores today (-730 and -670) due to differences of opinion about doubles. Well, I will admit that perfect--I would claim double-dummy--defense by me would have turned the second one into +200 (and 8/11 matchpoints).

We mostly make up for these setbacks with many tops of our own. Here are a couple which are entirely due to Harrison's good play.

First board. The unopposed auction is short and sweet: 2C--2D--2NT--7NT.  The lead is a small club, if I recall.

83 Q432 AQT6 AQ2

AKQJ4 AK6 J7 K95

Maybe there was some slight overbidding going on but don't worry. The play's the thing. There are an easy twelve tricks on top. The diamond finesse is a 50% shot. But, and Harrison figured this out in a couple of milliseconds: the spades will furnish three discards from dummy. That makes a Vienna Coup possible (cash DA and then pitch all of dummy's small diamonds).

But you need the same player to have the DK and the heart length. Doesn't that bring the probability down to 25%? No, that's the beauty of an automatic squeeze like the Vienna Coup, i.e. where dummy has an idle card and so doesn't have to commit a threat card before RHO plays. We can victimize either opponent this way, which means that the probability of success is back up to 50%. Indeed, the diamond King was off-side. But that player also had five hearts. Scoring up 1520 for all the matchpoints.

One other pair got to a making 7S but most were in 6NT making 6.

Two boards later. Partner's arithmetic seems to have gone off the rails a little and we end up in 4NT when everyone else will be in 6NT.

AK32 A862 J3 AQ2

QJ4 KQ7 AK85 963

The helpful lead is a small diamond which allows dummy's jack to score a trick. Now, we're up to 11 tricks. This time, the chances of making 12 tricks are basically 36% for a 3-3 heart split plus a few more percentage points for the same player having four hearts and KJT of clubs (or a very small chance of one player having a singleton club honor). Because that would allow for another Vienna Coup, either opponent will do as victim. The probability of success here is going to be something like 36% (hearts split) plus 64% x 12.5% (three specific cards in same hand as the heart length). That gives a total of 44%, not too bad actually. 

And so it proved. Harrison rectified the count at trick 2 by ducking a club to RHO's ten. He could always take the club finesse later if he wanted to. As it turned out, RHO had five hearts and the club ten. Maybe she'd have the K and J too.

This is where the beauty of a squeeze comes in. A finesse risks losing the lead, even to a stiff honor. But squeezes (mostly) don't give up the lead--you just keep playing and either the last trick comes out right or it doesn't. 

Harrison worked out one other thing. Almost everyone will be in 6NT and if the finesse of the king is on (and they receive a helpful diamond lead) they'll have 12 tricks in the bag. We basically cannot outscore those declarers. But, if the CK is indeed offside (knowing that RHO has the heart length), then we will likely outscore any pair that's not in slam and certainly all of the pairs that did bid the slam.

It's always fun and educational when I play with Harrison. I enjoy it to the max while I can!