[mikl_plkcc]

---

The robot refused to set the contract with the ♣A, and let them made the doubled game!

[jillybean]

Why torture yourself with bots?

[johnu]

Good defense by GIB to hold the contract to making 3. Lesser robots would have allowed an overtrick.

[smerriman]

There really should be a forum for GIB posting about all of the countless things its human partners do wrong.

[msheald]

Hello! For my own education, I'd be curious to know ops change in position should Gib have taken the setting trick. I have not looked at the hand closely, but it is possible that taking the ace would have opened up other lines of play. In the event that it would have been the setting trick, knowing the point change between the two outcomes would be helpful in knowing how to play with Gib in the future.

Lastly, it would be helpful for those with program simulators to run 5000 deals to see what average results would be with different lines of play. As David Bird notes in "Winning Duplicate Tactics," a single deal means nothing, but the good player plays to maximize outcome over many deals. Best regards.

Mike

[msheald]

No One?

[smerriman]

msheald, on 2025-July-17, 06:30, said:

Hello! For my own education, I'd be curious to know ops change in position should Gib have taken the setting trick. I have not looked at the hand closely, but it is possible that taking the ace would have opened up other lines of play. In the event that it would have been the setting trick, knowing the point change between the two outcomes would be helpful in knowing how to play with Gib in the future.

Lastly, it would be helpful for those with program simulators to run 5000 deals to see what average results would be with different lines of play. As David Bird notes in "Winning Duplicate Tactics," a single deal means nothing, but the good player plays to maximize outcome over many deals. Best regards.

Mike

GIB is not capable of deciding what tables other contracts are likely to be playing in (or how their play would have gone). Here, obviously, you'd expect all other humans to be playing 4♥. If that makes, anything but an impossible down 3 is a bottom. If it's going down, all that matters is that you beat 3♦; it makes no difference by how many tricks, even at MPs where the difference of a single trick is usually crucial to the score.

GIB instead assumes everyone else is in the same 3♦x contract it is, so if there's a line which gets down 2 52% of the time and lets 3♦ make 48% of the time, it considers that better in the long run than a guaranteed down 1.

It also doesn't understand South's double (though who does), or carding or declarer play logic, so thinks South is a slight favorite to hold the ♣J, despite the fact that leading the ten and declarer not covering would both be very unusual, among other inferences from the play.

And if South holds the ♣J, ducking beats 3♦ by more.

[msheald]

I was thinking that Miki_plkcc might be able to post his % without taking the ace clubs and what it might of been if the robot had taken the ace of clubs.

Mike

[Huibertus]

A bit late joining this threat.

First let's mention a bit of advice, it's well meant, don't take it too hard. If you want to improve as a bridge player you need to be able to find out what you do wrong rather then point out what partner did wrong. Too many of us are only capable of the latter. I hope you treat real life partners better than this bot.

So, first the bidding:

What is this double on 3♦ meant to do? IMO it is very ill advised.

You opened 15-17 balanced and so far partner has promised nothing except for 5 ♥s. Doubling to say "I still have 15 HCP" is nonsense, we shouldn't be doing that. So what should it mean given partner can have nothing? It should mean "within my range of bidding I have a LOT of defensive values against 3♦ and hardly any offensive values for our own contracts. And here's what probably made the bot duck ♣ Ace in the end, it just hadn't seen your defensive values yet and assumed you had 1/2 more trumps left to take care of the ♠ after which he could take ♣ Ace at a time all opponents trumps were gone to also cash some more ♥.

What you have in reality is the exact opposite. Due to the transfer KQX ♥ has become more offensive and less defensive then it was when you opened, ♠ Ace and ♦ Ace both are offensive cards rather then defensive only ♠ Q is a defensive card. It would NOT surprise at all if 3♦ goes with over tricks and 3♥ makes.

Doubling on this holding misinforms partner, he's more likely to make the wrong decision in bidding as well as during potential defensive play because of it. And it EVEN is more likely to hinder your own defensive play as we shall see.

So just pass, you have nothing to add to the bidding at this point. Now partner will come in, he will I assume double 3♦ as he's looking at the values for game, no known fit and no ♦ stopper.

After the bot doubled it is now up to you to decide what to do. You could bid 3♥ which leads to 4♥, I guess that is what most would do. You could consider 3NT for which clearly AT ♦ should not be considered good enough. Or you might pass, I'd have some sympathy for that at equal vulnerability, unclarity about you having the values for game and it being matchpoints.

So now lets look at defending 3♦ after partner, not you, doubled.

You still lead ♥ King at which point it still is on for +800. You now can have a look at dummy and deduce partner has ♥ Ace and ♣ Ace for his bidding. Which you wouldn't have known when YOU doubled. So now you know that unless declarer has ♦ Jack declarer has no entries (partner will not take ♣ K or Q but will take ♣ 6) and you plan to make use of it by continuing ♥, and you'll do it again after ♦ Ace.

Now should you fail to analyze you have to play ♥ again and again and play 2 rounds of trumps after ♥ King just like you did when it was a LOT harder to see it because you doubled yourself, then you are still on for +500 after scoring ♠ AQ just by giving partner trump promotion to score ♦ J by playing a 3rd round of spades. This too has become easier to find by not doubling 3♦ for no reason, after partner's double it is entirely possible he has ♦J, and it can't harm to try if he doesn't.

After you have given partner trump promotion it no longer is even possible to score less then +500 partner can no longer err and give away a trick.

Finally, when you didn't find the promotion too like you did when you doubled yourself, just say to partner "Sorry, I get your frustration and refusal to make ♣Ace after all my mistakes" when it repeats the same mistake.

[johnu]

smerriman, on 2025-July-19, 18:37, said:

And if South holds the ♣J, ducking beats 3♦ by more.

Yes, ducking the club gives the defense 2 club tricks if South has led 10 from ♣J10. Of course, in the real world, there's zero chance that South led 10 from ♣J10, but in GIB world, that must be around 50%, either South has the jack or South doesn't have the jack.