From just declare

[thorvald]

[hv=url=https://www.bridgebase.com/tools/handviewer.html?lin=st||pn|Thorvald,~~v3fakebot,~~v3fakebot,~~v3fakebot|md|1SAT864HDJ32CAQ752,SJ7HT72DAQT764CJT,S3HAQJ964DK95CK83,SKQ952HK853D8C964|sv|b|rh||ah|Board%207|mb|1S|an|Major%20suit%20opening%20--%205+%20!S;%2011-21%20HCP;%2012-22%20total%20points|mb|P|mb|2H|an|Forcing%20two%20over%20one%20--%205+%20!H;%2012+%20HCP;%2013+%20total%20points;%20forcing%20to%203N|mb|P|mb|2S|an|Opener%20rebids%20suit%20--%203-%20!H;%205+%20!S;%2011-21%20HCP;%2012-22%20total%20points;%20forcing%20to%203N|mb|P|mb|2N|an|5+%20!H;%2012+%20HCP;%2013+%20total%20points;%20forcing%20to%203N|mb|P|mb|3C|an|4+%20!C;%203-%20!H;%205+%20!S;%2011-21%20HCP;%2012-22%20total%20points;%20forcing%20to%203N|mb|P|mb|3H|an|12+%20HCP;%20twice%20rebiddable%20!H;%2013+%20total%20points;%20forcing%20to%203N|mb|P|mb|3S|an|4+%20!C;%203-%20!H;%2011-21%20HCP;%20twice%20rebiddable%20!S;%2012-22%20total%20points;%20forcing|mb|P|mb|4S|an|2+%20!S;%2012+%20HCP;%20twice%20rebiddable%20!H;%2013-18%20total%20points|mb|P|mb|P|mb|P|pc|DA|pc|D5|pc|D8|pc|D2|pc|CJ|pc|CK|pc|C4|pc|C2|pc|HA|pc|H5|pc|S4|pc|H2|pc|SA|pc|S7|pc|S3|pc|S5|pc|S8|pc|SJ|pc|H4|pc|S9|pc|DQ|pc|DK|pc|S2|pc|D3|pc|SK|pc|S6|pc|D7|pc|H6|pc|SQ|pc|ST|pc|D6|pc|H9|pc|HK|pc|C5|pc|H7|pc|HJ|pc|C9|pc|CQ|pc|CT|pc|C3|mc|7|]399|300[/hv]

 

From the Just Declare, so all bidding by bots.

 

It loooks like the bot can't bid 3♣ as it would promise extra, so it had to rebid 2♠

 

Now 2N seems a fine bid and 3♣ is fine

 

North now would like to check for 6-2 in ♥, so rebids 3♥

 

Now south has a problem, where most probably would bid 3N hoping Jxx is a stopper, but the bot rebids 3♠

 

For some strange reason North thinks 3♠ is a rebiddable suit and prefers 4♠ to 3N

 

Of couse all have to declare the same contract, and some might even realise they are not playing 3N :-)

[smerriman]

Is there something you think is a bug here?

 

If you think the bug is that South should bid 3nt, as far as I can tell it does, most of the time.

 

If you think it's North final decision which is a bug, well, it simulates that most of the time South indeed has 6 spades, and 4S will work better.

 

So not seeing anything particularly wrong.

[thorvald]

I think that both 3♠ and 4♠ are errors. But as 4♠ is a simulation based on 3♠ typical being rebiddable ♠ we are down to 3♠ is an error

 

3N in this sequence does not promise anything about ♦ as partner did bid 2N

 

If not 3N, then I think 4♣ is a better descriptive bid

 

https://bridgewinner...278770#c1278770

[smerriman]

I think that both 3♠ and 4♠ are errors. But as 4♠ is a simulation based on 3♠ typical being rebiddable ♠ we are down to 3♠ is an error

3♠ is based on a simulation too, and like I said, the result of this is 3N most of the time (4♣ did pop up too). So no bug, just another outlier.

[thorvald]

3♠ is based on a simulation too, and like I said, the result of this is 3N most of the time (4♣ did pop up too). So no bug, just another outlier.

 

It could be interesting to know the hands that got the simulation.to that result.

 

If you look at the explanation of Norths bid you will notice that 2N does not limit the hand to 2♠ as I think it should

 

 

 

[smerriman]

It could be interesting to know the hands that got the simulation.to that result.

 

If you look at the explanation of Norths bid you will notice that 2N does not limit the hand to 2♠ as I think it should

None of the simulated hands have North holding 3 spades, so no issues there.

 

Had it run it about 20 times before it came up with a conclusion of 3♠ rather than 3N or 4♣, but the time it did, 3 of the hands were:

 

[hv=?n=sk5hkjt982da7ckjt&s=sat864dj32caq752&w=sj92haq753dk984c6&d=s&v=b&a=1sp2hp2sp2np3cp3hp3sp4sppp]400|300[/hv]

extrapolates 3♠ raised to 4♠ for +620, 3NT passed for -100, 4♣ raised to 5♣ for -200

 

[hv=?n=sk5haj5432dat5ck4&s=sat864dj32caq752&w=sj97hq9dk874ct983&d=s&v=b&a=1sp2hp2sp2np3cp3hp3sp4sppp]400|300[/hv]

extrapolates 3♠ raised to 4♠ for +620, 3NT passed for -100, 4♣ corrected to 4♠ for +620

 

[hv=?n=sk5hat8532dat7ck4&s=sat864dj32caq752&w=sj9h64dkq64cjt963&d=s&v=b&a=1sp2hp2sp2np3cp3hp3sp4sppp]400|300[/hv]

same as case 2

 

[hv=?n=sqhkjt853daq5ck83&s=sat864dj32caq752&w=s953h762dt84cjt96&d=s&v=b&a=1sp2hp2sp2np3cp3hp3sp3nppp]400|300[/hv]

In this case, it predicts North will correct 3♠ to 3NT, so both spade and NT bids are fine - but 4♣ will result in going down in a club game.

 

There were also some hands where both 3NT and 4♠ made, but there were only 9 tricks available in NT, meaning a small win for 4♠, like:

[hv=?n=skhaj7643dk9cjt43&s=sat864dj32caq752&w=sqj52hqt9852da4c9&d=s&v=b&a=1sp2hp2sp2np3cp3hp3sp4sppp]400|300[/hv]

 

Plenty of hands where both options led to the same score (eg down 1) too.

 

Of course, there were also hands where 3♠ is worse, and in almost all simulations these come up often enough to make it choose 3NT.. the point is, no matter what the odds, there's always a small percentage of the time a simulation will come up with the wrong conclusion, even if the bidding system is perfect.

 

And of course, many of the outcomes aren't what would really happen, but only with double dummy play, but you can't help that.

[thepossum]

I never assumed that Just Declare auctions were real

Given the nature of some contracts they even appear beyond GiB

What kind of person would contrive hands to trip up a bot :)

Come up with a weird auction and reverse engineer a hand that kind of fits maybe