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GIB grossly undervalues its hand

#1 User is offline   wbartley 

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Posted 2018-February-26, 17:05

Just Play Bridge robot. Human South.



After the brilliant trump lead and the play of the J of clubs from robot East the hand makes 6. It's hard to imagine how raising to 3 with king third of clubs, a side bullet and the presumably well placed king of spades could be wrong here.

And before the obligatory and irrelevant comments about South's 2 bid get started, The hand makes 5 on any lead if South holds xxxx Ax x AQT98x and West, AQJTx of spades.
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#2 User is offline   pescetom 

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Posted 2018-February-27, 10:18

You ask not to comment the 2 bid so I won't, but surely it is South and not North who grossly undervalues his hand.
North already passed, then doubled spades, now he looks at his 8-losers, 3-card fit and no stopper in the promised hearts and decides that discretion is the better part of valour: hard to blame him IMO.
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#3 User is offline   wbartley 

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Posted 2018-February-27, 12:05

View Postpescetom, on 2018-February-27, 10:18, said:

You ask not to comment the 2 bid so I won't, but surely it is South and not North who grossly undervalues his hand.
North already passed, then doubled spades, now he looks at his 8-losers, 3-card fit and no stopper in the promised hearts and decides that discretion is the better part of valour: hard to blame him IMO.


Please show me a South hand consistent with the bidding where 3 isn't as cold as ice.
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#4 User is offline   manudude03 

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Posted 2018-February-27, 12:28

View Postwbartley, on 2018-February-27, 12:05, said:

Please show me a South hand consistent with the bidding where 3 isn't as cold as ice.


Qx KJx Qx AJTxxx is potentially losing 1 spade, 2 hearts, 1 diamond and 1 club.
Wayne Somerville
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#5 User is offline   pescetom 

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Posted 2018-February-27, 13:44

View Postwbartley, on 2018-February-27, 12:05, said:

Please show me a South hand consistent with the bidding where 3 isn't as cold as ice.


View Postmanudude03, on 2018-February-27, 12:28, said:

Qx KJx Qx AJTxxx is potentially losing 1 spade, 2 hearts, 1 diamond and 1 club.


And in any case North doesn't raise a non-forcing 2 bid just because 3 should make.
Either he sees a real prospect of making 5 or he thinks there is a chance of 3NT.
In this case he sees little chance of game and he will be afraid that you might raise 3 to 3NT on the assumption that he can stop hearts.
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#6 User is offline   wbartley 

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Posted 2018-February-27, 17:09

View Postmanudude03, on 2018-February-27, 12:28, said:

Qx KJx Qx AJTxxx is potentially losing 1 spade, 2 hearts, 1 diamond and 1 club.


That hand is pretty much impossible. East would have to have 3 or 4 card support for spades and not raise.
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#7 User is offline   wbartley 

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Posted 2018-February-27, 17:10

View Postpescetom, on 2018-February-27, 13:44, said:

And in any case North doesn't raise a non-forcing 2 bid just because 3 should make.
Either he sees a real prospect of making 5 or he thinks there is a chance of 3NT.
In this case he sees little chance of game and he will be afraid that you might raise 3 to 3NT on the assumption that he can stop hearts.


With Txxx of hearts, I wouldn't worry about my partner bidding 3NT with Qx
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#8 User is offline   Stefan_O 

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Posted 2018-March-01, 17:28

View Postwbartley, on 2018-February-27, 12:05, said:

Please show me a South hand consistent with the bidding where 3 isn't as cold as ice.


I'm not sure that is relevant, since playing 3 will never give you more points than playing 2.

The issue should rather be, are there any hands consistent with the bidding where can make more points in a different contract -- here meaning, we might have a game in the cards?

Over 2,
I would think Gib runs a "simulation" over a number of deals consistent with its own hand and the bidding,
and passes because game-chances seem to remote.
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#9 User is offline   Stefan_O 

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Posted 2018-March-01, 17:33

View Postwbartley, on 2018-February-27, 17:09, said:

That hand is pretty much impossible. East would have to have 3 or 4 card support for spades and not raise.


I also doubt Gib is programmed to draw such inferences from players not bidding.

It will recognize a passed hand cannot have more than some 11 hcp, but otherwise, I don't think so.
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#10 User is online   smerriman 

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Posted 2018-March-01, 18:22

View PostStefan_O, on 2018-March-01, 17:28, said:

Over 2,
I would think Gib runs a "simulation" over a number of deals consistent with its own hand and the bidding,
and passes because game-chances seem to remote.

Let's play bridge robots = basic robots = no simulations during bidding, so that's not the case here.

The description of 3 is actually compatible with GIB's hand, so it's hard to know when GIB chooses to bid it and when it chooses to pass.

But if you want GIB to take into account things like cards being more valuable over the doubler, you'd need the advanced bots, where it will run simulations of possible opponents hands and use them to decide whether it's worth pressing for game or not.
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