[H_KARLUK]

Scoring: Total Points

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Uncontested

1♦-1♠
1NT-2♣
2♠-3NT
4♠ AP (10 tricks taken +420)

Adios 7♣

Seriously, I don't want to jump any quick conclusion, however, what's goin' on there please?

[helene_t]

Looks as if GIB plays MAFIA (a 2♣ response would deny a 4-card major). I wasn't aware of that.

After your 1NT rebid, 2♣ is the only forcing bid it has so that is normal.

After 2♠ I think it just made some simulations and found 3NT to score a little better than 6♣ on average.

These things happen all the time. You might have made GIB a little more enthusiast by opening 1NT

[H_KARLUK]

helene_t, on Feb 21 2010, 06:13 PM, said:

Looks as if GIB plays MAFIA (a 2♣ response would deny a 4-card major). I wasn't aware of that.

After your 1NT rebid, 2♣ is the only forcing bid it has so that is normal.

After 2♠ I think it just made some simulations and found 3NT to score a little better than 6♣ on average.

These things happen all the time. You might have made GIB a little more enthusiast by opening 1NT

Wait a minute please.

Scoring: Total Points

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Did you mean with this layout GIB is unable to find the best contract? Is GIB able to see I've 15 or 13 balanced ?

[helene_t]

GIB assumes you have 12-14 points. With 15 you open 1NT in the GIB system.

GIB doesn't know that clubs are 2-2. On the other hand you could have had three or four clubs, or ♣Q. So I think in most of its simulations there are no club loses.

There could of course easily be a spade loser (there will be one more often than not I think) and possibly one or even two heart losers. Sometimes a heart goes away on ♦A if you have that card, but remember that GIB makes its decisions on DD analysis, so opps will always lead a heart when that is right.

I think given your 1NT rebid and 3-card spade support, 6♣ has more than 50% chance. It is not shocking that the simulations can turn out with less than 50%. Maybe more to the point, GIB should probably have bid 3♣ over 2♠. Not sure why it didn't. Maybe that would imply five spades it which case it's a fault in its system. While 4♣ would of course be a splinter. I am just speculating.

[PhantomSac]

So you downgraded/were unable to count and missed a slam...wow!

[arigreen]

This was a somewhat difficult hand for GIB to bid:

1) Over 1♦ GIB prefers bidding a 4-card major to responding 2♣. Most of the time this works reasonably well. GIB's system is incomplete after 1♦-2♣ -- in fact, this auction is not GF.

2) Over 1NT, GIB plays one-way new minor forcing. 3♣ over 1NT would have been to play.

3) Over 2♠, 3♣ by GIB would have been NF invitational and 4♣ would have been a splinter agreeing spades. For various reasons, GIB decided not to simulate but instead bid 3N according to the book bid.

If GIB had simulated here, it surely would have judged to bid on towards slam.

[barmar]

Although 1♦-2♣ isn't game forcing, it should be a one-round force, and when GIB reverses with 2♠, that should establish a GF. But as we've seen in another thread, GIB doesn't even think 2♣ is a 1RF, so I can see how this would be a problem.

Fix the problem with 1♦-2♣ and maybe everything else will fall into place.

[hanp]

H_KARLUK, on Feb 21 2010, 05:01 PM, said:

1♦ 
4♠

The onion's telling the cabage that she smells badly.

[jdonn]

He made 4♠ in a 4-3 fit despite the 5-1 break. You were lucky to have such a good partner. He probably wonders whether you are his 3rd opponent since you forgot to open 1NT and if you had he would have bid slam.

[Bbradley62]

arigreen, on Feb 22 2010, 09:55 PM, said:

For various reasons, GIB decided not to simulate but instead bid 3N according to the book bid.

I'm not the same level player as the rest of you, but I'm enjoying reading all of your posts on this and other hands, and wanted to ask about this.

Does "the book" really say to never mention your good 7-card minor when your partner has shown 2-4 of them?

I've never played a total points event except for BBO's free robot race, but I'd expect it to even more safety-based than IMPS. If that's the case, and North wants to bid game but not slam, why wouldn't he blurt out 5♣ instead of 3NT?

[barmar]

I don't think GIB takes the form of scoring into account in its strategy.

[Bbradley62]

If GIB does simulations and makes decisions based on simulated results, it must be using some form of scoring to make those decisions. What form does it use?

[helene_t]

I would think it uses total points. Other scorings are dubious as the optimal strategy depends on assumptions about what happens at the other tables. Probably for IMP scoring, it would be slightly better to optimize IMPs based on the assumption that the other tables are faced with the same dilemma. At matchpoints, this can lead to scissors-stones-paper situations where an optimum does not exist, and I should think that theoretically the same could happen at IMPs although it is less likely to. So maximizing total points is simpler and it doesn't make much of a difference.

[Bbradley62]

I know they haven't had enough time to respond yet, but I was hoping that a programmer would say "This is what GIB does..." rather than two different people guessing.

[jdonn]

Bbradley62, on Mar 3 2010, 02:16 PM, said:

I know they haven't had enough time to respond yet, but I was hoping that a programmer would say "This is what GIB does..." rather than two different people guessing.

The programmer is arigreen, the 6th post in this thread.

[agusaris]

GIB programme on my computer ( not online) bid this as follows

1 Diamond 2 Clubs

2 Diamonds 2 Spades

3 Hearts 6 Clubs

Not too bad. ( Incidentally has no one noticed that East and South have the Queen of hearts )

[Bbradley62]

jdonn, on Mar 3 2010, 02:23 PM, said:

Bbradley62, on Mar 3 2010, 02:16 PM, said:

I know they haven't had enough time to respond yet, but I was hoping that a programmer would say "This is what GIB does..." rather than two different people guessing.

The programmer is arigreen, the 6th post in this thread.

Yes, I did recognize that. But in response to his post, I asked about form-of-scoring affecting the auction. I'm not criticizing the staff in any way, just hoping to get a clear answer so I understand the GIB better.