[thorvald]

In the WBC-1000 tournament I lost heavily on these two boards. I don't think I did anything stupid, but my opponent managed to get the bot to play differently and won both contracts

First

---

We both bid to the normal 4♥, and East found the killing ♣-lead.

I played ♥10 to the J, and Wests King. The Bot switched to a ♦ and got a ♣-ruf, One down - nice defense.

My opponent played a small ♥ to the Ace and continued ♥, where the bot used ♥K and continued ♥, 10 tricks and 12 IMP out.

The play of the cards gives 2 different simulations, but the bot knows the same about the hands in the 2 situations, yet East had one more discard against my opponent, but getting the ruff seems the be best chance to defeat the contract.

Then secondly

---

Again the bidding was the same at both tables. After the ♣ lead I played ♥J and mis guessed the ♥s. With ♠s 5-0 there was no way home.

But again I was outplayed by my opponent as declarer played a ♠ to the King at trick 2. Unblocked ♦AK, ruffed a ♣, and dropped a ♥ on ♦Q. Now when declarer played ♥J from dummy East flew the ♥A, and declarer had 10 tricks, and I lost 10 Imps.

Perhaps it is a good rule to postpone guesses to the latest moment as bots is having trouble finding the best defense, even knowing more about the hands.

I will be back for next tournament :-)

[TylerE]

If the auctions were the same, how do you play it at one table and the bot at the other?

[smerriman]

TylerE, on 2023-March-21, 22:42, said:

If the auctions were the same, how do you play it at one table and the bot at the other?

? He didn't.

First one is just random, nothing to do with what you did.

The second one makes sense though; GIB knowing more about the hand is precisely why it plays the ace. East can never tell if one card would put you to more of a guess than another card if both are double dummy equals. It bases its choices solely on the rare cases where one is actually better than the other. These rare exceptions can easily swing the result either way, and there are definitely less exceptions later on.

Of course, East can beat you by ruffing a spade at trick 2, so it's not without risk..

[TylerE]

"The play of the cards gives 2 different simulations, but the bot knows the same about the hands in the 2 situations". If the auctions were not identical that is an invalid assertion.

[smerriman]

TylerE, on 2023-March-22, 09:02, said:

"The play of the cards gives 2 different simulations, but the bot knows the same about the hands in the 2 situations". If the auctions were not identical that is an invalid assertion.

He said they both bid the same, so the auctions were identical? Really not sure what you're getting at.. from both your comments I think you've totally misread the post.

And you cut off the key part of the sentence which says 'yet East had one more discard against my opponent'.

This discard changes absolutely nothing about the hand in a bridge sense, just that it forces a new set of simulations, which is precisely what Thorvald was saying by the first half of the sentence.

He was asking whether one simulation was more likely than the other to get to desired outcome. In hand 1, no. In hand 2, yes.