[campboy]

mycroft, on 2014-January-14, 14:47, said:

I've been in several contracts where, because I know I'm in a matchpoint inferior contract, I play for the "right" contract to go down, even if it means I slip a trick 90+% of the time (because, frex, +650 is as much of a bottom as +680, so let's play for everything wrong and the slam fails).

Does that work? Surely if everything's wrong and the slam fails +620 is just as much of a top as +650. Shouldn't you just ignore all the tables in slam, since what you do won't affect whether you beat them?

[Vampyr]

jeffford76, on 2014-January-14, 15:18, said:

There was an interesting story on BridgeWinners about someone who was in one contract and suspected that the score was going to be adjusted to a higher one after their partner used UI, so they played to make the higher contract (which was anti-percentage for their lower contract but it worked) because they didn't want to count on the director to assign them the correct line in the higher contract as the offending side. There were mixed reactions on whether this was ok.

I cannot work out how this would be illegal, but it is pretty smelly.

[blackshoe]

jeffford76, on 2014-January-14, 15:18, said:

There was an interesting story on BridgeWinners about someone who was in one contract and suspected that the score was going to be adjusted to a higher one after their partner used UI, so they played to make the higher contract (which was anti-percentage for their lower contract but it worked) because they didn't want to count on the director to assign them the correct line in the higher contract as the offending side. There were mixed reactions on whether this was ok.

Vampyr, on 2014-January-15, 05:11, said:

I cannot work out how this would be illegal, but it is pretty smelly.

AFAICS, it's not illegal. As for smelly, well, it's 6 AM and I've been up all night, so maybe I'm missing something. How is it smelly? In particular, under ACBL rules, which stipulate that you must play every hand to win, how can it possibly be "smelly" to do that?

[barmar]

campboy, on 2014-January-15, 04:20, said:

Does that work? Surely if everything's wrong and the slam fails +620 is just as much of a top as +650. Shouldn't you just ignore all the tables in slam, since what you do won't affect whether you beat them?

I think the idea is that if you expect the field is in slam, and it makes on normal lies of the cards, you have to assume that there's a strange lie that causes it to go down. Then you play to make your contract with that lie, which could involve making very anti-percentage plays. If the field is bidding and making slam, you get the same bottom whether you make your game or go down.

[aguahombre]

barmar, on 2014-January-15, 10:36, said:

I think the idea is that if you expect the field is in slam, and it makes on normal lies of the cards, you have to assume that there's a strange lie that causes it to go down. Then you play to make your contract with that lie, which could involve making very anti-percentage plays. If the field is bidding and making slam, you get the same bottom whether you make your game or go down.

I have a different idea. Once the auction is over, I am now competing for more or fewer matchpoints against those pairs who did not bid slam. I don't want to lose to those pairs too; and, at the bar, I don't want to hear, "You were wise not to bid slam. It was a tribute to your play."

[GreenMan]

aguahombre, on 2014-January-15, 11:03, said:

I have a different idea. Once the auction is over, I am now competing for more or fewer matchpoints against those pairs who did not bid slam. I don't want to lose to those pairs too; and, at the bar, I don't want to hear, "You were wise not to bid slam. It was a tribute to your play."

This only works if you figure some portion of the field will be with you in game rather than slam. If not, barmar's strategy is superior.

[Vampyr]

GreenMan, on 2014-January-15, 11:31, said:

This only works if you figure some portion of the field will be with you in game rather than slam. If not, barmar's strategy is superior.

At matchpoints, the normal line will give barmar a top if everyone else is in slam, since he will go down fewer.

[GreenMan]

Vampyr, on 2014-January-15, 11:38, said:

At matchpoints, the normal line will give barmar a top if everyone else is in slam, since he will go down fewer.

If everyone in slam is going down, then either line produces a good matchpoint score vs. those pairs. But +680 also beats -50, so you might as well play for it.

[mycroft]

If it's between +620 and +650, sure. Play to "go down less", or "beat the rest of the lousy bidders".
If it's between +650 and +680, now you're not going down less if the 90% line makes.

If you bid as badly as at least some of the field, sure, take your MPs for at least tying them. But when, in a Precision auction that shows us that we shouldn't be in slam, dummy comes down and it's obvious that everyone playing "standard" is going to *be* in that slam, you play to make 5, especially when the finesse you knew you needed that the standard people didn't know about in the auction works.

Frankly, that's the hardest part of playing Precision, or some other odd system, in a Standard world - when the system gives you a problem, it's frequently a problem the standard people won't know enough to have. So you can either trust your system and play top/bottom, or you can go with the field, give up the system advantage, and play for A+. Sure, there are hands where the system makes it automatic, and it's the standard players that have a problem, but they're secure in the knowledge that half the field will go with them, whichever way they choose.

[Vampyr]

mycroft, on 2014-January-15, 12:06, said:

If it's between +620 and +650, sure. Play to "go down less", or "beat the rest of the lousy bidders".
If it's between +650 and +680, now you're not going down less if the 90% line makes.

Sorry if I'm missing something, but I don't see the difference. The people in slam are no longer in the field in shich you are competing.

Quote

So you can either trust your system and play top/bottom, or you can go with the field, give up the system advantage, and play for A+. Sure, there are hands where the system makes it automatic, and it's the standard players that have a problem, but they're secure in the knowledge that half the field will go with them, whichever way they choose.

You are playing a different system to the rest of the field because you want to win the board in the auction. If that doesn't happen, then you should of course try for A+ rather than top or bottom. But again, I must be missing something.

[GreenMan]

Vampyr, on 2014-January-15, 12:24, said:

Sorry if I'm missing something, but I don't see the difference. The people in slam are no longer in the field in shich you are competing.

The scenario this discussion originated from was one where you're in a field of essentially 1. If no one else is in the same contract as you, you don't have to worry about what those nonexistent people will do.

The calculations change with your estimation of how many of the field are in the "right" contract, and you figure the probabilities accordingly. But in the basic problem, you're trying to beat the majority.

[barmar]

GreenMan, on 2014-January-15, 12:43, said:

The scenario this discussion originated from was one where you're in a field of essentially 1. If no one else is in the same contract as you, you don't have to worry about what those nonexistent people will do.

Or a small field. If 90% of the field is in slam, and it makes, then you're just competing for the difference between a bottom and 10%. That difference is probably not worth worrying too much about.

So instead, you assume that the slam is not making. Then you play to make your contract on that assumption. You can take big chances if means gaining 80% versus losing 10% if you're wrong. It's similar to the strategy you take at IMPs when you've overbid to a shaky game: a 10% chance to get the game bonus is better than nothing.

Where it becomes interesting is if it's a 4-or-6 hand, and it just depends on a particular decision, and you're in 5. The people in slam will obviously try to make 6. You have to figure out what line they'll take, and do the opposite. E.g. if slam makes unless there's a kingleton offside, you try to drop it.

[CSGibson]

barmar, on 2014-January-16, 13:12, said:

Or a small field. If 90% of the field is in slam, and it makes, then you're just competing for the difference between a bottom and 10%. That difference is probably not worth worrying too much about.

So instead, you assume that the slam is not making. Then you play to make your contract on that assumption. You can take big chances if means gaining 80% versus losing 10% if you're wrong. It's similar to the strategy you take at IMPs when you've overbid to a shaky game: a 10% chance to get the game bonus is better than nothing.

Where it becomes interesting is if it's a 4-or-6 hand, and it just depends on a particular decision, and you're in 5. The people in slam will obviously try to make 6. You have to figure out what line they'll take, and do the opposite. E.g. if slam makes unless there's a kingleton offside, you try to drop it.

Barry, this doesn't make any sense.

All that is ever at stake on your line of play is the 10%. Now, are you willing to lay 9-1 odds on a line of play based on gaining/losing 10% of a board? It doesn't matter if the variance is between 80-100 or 0-20, 10% is on the line, the other 80% is out of your control.

Now you may decide that you are not going to win anything if you are in the 0-20 range anyway, and make a line of play to maximize your chances in the event that you are in the 80-100 range, but that feels like a last round strategy and not a general wise overall strategy, because you're EV from the line is negative.

Likewise with your 4 or 6 decision. I'm willing to bet that the decision that maximizes your potential matchpoints on the hand is to take the highest percentage line of play.

[ArtK78]

At matchpoints, what you don't want to do is adopt a line that will result in down 1 when the people in slam will go down 1 on a normal line of play for slam.

At IMPs, the issue is different. This past Sunday, i was playing in a Swiss Team event in Philadelphia. Due to a bidding misunderstanding, my partner wound up declaring 5♥ when 6♥ was the normal contract. He didn't give the hand much thought and took the "normal" line of play - the line of play that would result in 12 tricks on a reasonably normal lie of the cards. In fact, the lie of the cards was so unfriendly that the normal line of play for slam results in 10 tricks, and that is what he made. So we gained 100 points as he was down 1 in 5♥ while our opponents were down 2 in 6♥ - a gain of 3 IMPs. However, there was a much better line of play for 11 tricks which would have succeeded, in which case we would have gained 13 IMPs - +650 and +200.

[barmar]

Maybe I'm not coming up with good examples, but I'm sure I remember reading in some book on matchpoint strategy that there are times when you have to adopt a strange line to make up for misbidding to a poor contract, based on the assumption that the field will be in the normal contract. Perhaps my inability to come up with an example is why I'm not a great MP player.

[Vampyr]

barmar, on 2014-January-17, 10:02, said:

Maybe I'm not coming up with good examples, but I'm sure I remember reading in some book on matchpoint strategy that there are times when you have to adopt a strange line to make up for misbidding to a poor contract, based on the assumption that the field will be in the normal contract. Perhaps my inability to come up with an example is why I'm not a great MP player.

I think that the most common occurrence of this sort of thing is when you are in, say 3NT and it is pretty clear that the field will be in 4 Major. Now you must score better in your contract and are willing to take considerable risks to do so.

[GreenMan]

barmar, on 2014-January-17, 10:02, said:

Maybe I'm not coming up with good examples, but I'm sure I remember reading in some book on matchpoint strategy that there are times when you have to adopt a strange line to make up for misbidding to a poor contract, based on the assumption that the field will be in the normal contract. Perhaps my inability to come up with an example is why I'm not a great MP player.

Klinger's book on matchpoint tips has a few examples. I don't have it handy or I'd provide one.

[gnasher]

jeffford76, on 2014-January-14, 15:18, said:

There was an interesting story on BridgeWinners about someone who was in one contract and suspected that the score was going to be adjusted to a higher one after their partner used UI, so they played to make the higher contract (which was anti-percentage for their lower contract but it worked) because they didn't want to count on the director to assign them the correct line in the higher contract as the offending side. There were mixed reactions on whether this was ok.

I think this is absolutely fine. You know that for the purpose of assigning a score you will be in the higher contract. Why shouldn't you play to make that contract?

[GreenMan]

Here's one from 50 Winning Duplicate Tips by Klinger (tip 32):

---

Declarers in 4♠ will take 12 tricks if the club finesse works, otherwise 11. You're booked for 11 or 10, respectively, if you take the finesse, so you play clubs from the top. The only problem if you do drop the Queen is that partner may keep bidding like that.

[ArtK78]

GreenMan, on 2014-January-17, 14:06, said:

Here's one from 50 Winning Duplicate Tips by Klinger (tip 32):

---

Declarers in 4♠ will take 12 tricks if the club finesse works, otherwise 11. You're booked for 11 or no more than 10, respectively, if you take the finesse, so you play clubs from the top. The only problem if you do drop the Queen is that partner may keep bidding like that.

FYP. They may have diamonds to cash if they led a diamond and you lose the club finesse.