smerriman

4♠ is basic GIB's bid. So the first question is whether advanced GIB actually simulated at all.. you'd think it should in this scenario. Though I tried to simulate myself through dealer.php and every time it generated a million hands, it would often come up with 0, sometimes 1 hand which matched the bidding (after 15 seconds). Don't know how it works on GIB's side, but maybe it failed to find enough matches in whatever time it has available and so reverted to the book bid..

If 90% of the time you want to attack the suit you led, then it doesn't seem to serve much purpose to have an odd pip represent this. If you *do* lead an even card, you're probably still wanting partner to continue attacking that suit, since the chances that you simply didn't have an odd pip probably outweigh the chances you didn't want the suit returned.

Oops, missed that. But I still disagree. OK, suppose you allowed someone to enter solely an HCP range and suit lengths ranges for a 1♣ opening. I enter 10-20, 5+ spades, 4+ diamonds. No robot in the world could ever be designed to have a dynamic bidding system that could compete against that and we're only at the second call in the auction.. Let alone more complex stuff like a bid which shows length in unspecified suits.

GIB doesn't deal hands based on HCP and suit lengths; it deals hands based on whether they would have resulted in a matching auction sequence. And to match the auction, it needs to have an entire database built around that bid. And the database doesn't have HCP and suit lengths 'variables' that it can simply change and have the rest adapt automatically; it's all around sequence matching. So you're basically starting that chunk from scratch. Making a simple bug fix seems extremely hard already, so adding an entire new branch of the database with every followup and defense - and not just that, but adjusting all the sequences where that bid *isn't* made anymore - is basically impossible.

The GIBson algorithm kicks in after the first 2 tricks (or maybe it's 3; definitely less than 10) for the advanced robots so as mentioned earlier that's not really a valid explanation.

Anyone? Yes. But the only people that can don't :( Can try to invent an explanation, like it rules out West having the ♥K from the lead, thus double dummy says both a diamond and a club are +1 until half a trick later when suddenly it isn't, but Advanced GIB is programmed to avoid that type of logic, and we've already seen other cases where GIB chooses a card that is strictly worse than another card in every possible arrangement of cards.

It happens now and then, and nobody knows why :(

Yep, this is about as far from 'possible', 'quick', and 'easy' as you can get :) If you want to play against robots, you'll need to play their system or accept very weird things will happen.

In bridge every convention has to be written in your head - referring to notes is cheating! Everyone will make mistakes and forget things. The key is not just learning a new 'rule' that is easily forgotten (show the Q with a 10 card fit), but making sure you understand why it applies (partner is trying to know if you have an extra potential loser in trumps; you don't with AKxxx with xxxxx). Then when that situation reoccurs, it will be easier to remember how to respond even if you forget the rule - just take a couple of extra seconds to think about what partner is asking for. This was covered in the first two threads, but there you were focused more on everyone else being wrong than why they were right. Based on your response this time you're making progress :)

GIB never gets the queen response wrong. As you know based on several of your threads on this in the past, it "shows the queen" when there is a guaranteed 10+ card trump fit, just like humans do.

Just remove the e=xxx and w=xxx hands from the URL, keeping the p=xxx played cards, so you get a URL like this: https://www.bridgebase.com/tools/handviewer.html?s=SAQ8HT4DKQJT87C82&n=SK94H87D64CAQT743&d=e&v=n&b=2&a=1H2D2HPPD3C4CPPDPP4DDPPP&p=S3S4STSADKD9D4D5DQH6D6D2DJS5C3DAHKH4H2H7H5HTHAH8H3C4HJD7DTS6C7D3C2C5CQC9S9S2SQS7D8C6CTSJC8CKCAHQSKH9S8CJ s=SAQ8HT4DKQJT87C82 south's hand n=SK94H87D64CAQT743 north's hand d=e dealer v=n vulnerability (n, e, b for both, or leave out) b=2 board number a=1H2D2HPPD3C4CPPDPP4DDPPP auction, alerts follow each bid in brackets (url-encoded) p=S3S4STSADKD9D4D5DQH6D6D2DJS5C3DAHKH4H2H7H5HTHAH8H3C4HJD7DTS6C7D3C2C5CQC9S9S2SQS7D8C6CTSJC8CKCAHQSKH9S8CJ played cards

You want ]400|300[/hv].

OK, lots of math ahead, either this is right or I'm going to look very silly, but hey: Suppose that declarer plays the J with probability p. Suppose East holds precisely Q95 of diamonds. If East plays low, declarer can cover cheaply 7/10 of the time and always win; the other 3/10 he can't and will always fail. So East should play the 9 if p > 3/10. Going over each holding we get: Q93: 0 Q92: 0 Q942: 0 Q932: 0 Q94: 1/10 Q952: 1/6 Q95: 3/10 Q962: 1/2 Q96: 3/5 Each of these 9 holdings is equally likely, and contributes 2/3 towards the queen being held, and 1/3 towards the queen not being held by restricted choice. Or basically, if we multiply by 27, we can count 2 for each queen, and 1 for each non-queen. So we just need to sort out what the optimal p is in each range. If p>3/5, East will play the 9 in all cases. East has the queen 18/27 times, which is a majority, so declarer wants to minimise p. The best p in this range is thus 3/5, and declarer wins 18/27 * 2/5 + 9/27 * 3/5 = 7/15. If p is between 1/2 and 3/5, we rule out the Q96 case (but still include T96), so the denominator becomes 25. East has the queen 16/25 times, so again we want to minimise p to be 1/2. Declarer wins 16/25 * 1/2 + 9/25 * 1/2 = 1/2. If p is between 3/10 and 1/2, East has the queen 14/23 times, so p = 3/10 and declarer wins 14/23 * 7/10 + 9/23 * 3/10 = 25/46. If p is between 1/6 and 3/10, East has the queen 12/21 times, so p = 1/6 and declarer wins 12/21 * 5/6 + 9/21 * 1/6 = 23/42. If p is between 1/10 and 1/6, East has the queen 10/19 times, so p = 1/10 and declarer wins 10/19 * 9/10 + 9/19 * 1/10 = 99/190. If p is less than 1/10, East has the queen 8/17 times, which is now less than half, so declarer wants to maximise p, so p = 1/10 again and declarer wins 8/17 * 9/10 + 9/17 * 1/10 = 81/170. Note those last two endpoints don't match up for p = 1/10, because it gives East a choice of two options.. it's possible I've made a mistake but I think it's just because we're solely restricting to the case where declarer has 32 in the final outcome, whereas East is optimising all cases. So overall declarer should play the Jack with a probability somewhere between 1/6 and 3/10 of the time, and will succeed in 23/42 of the relevant cases. [late edit] Found a mistake; that's assuming declarer doesn't vary p based on the spots he himself holds. So need to factor that in too somehow..

Second attempt. The relevant cases are T9x and Q9x, where x<7 (would play the 7 otherwise). East will always play high from T9x. Suppose the answer to this question is that declarer should always play the J. East, knowing this, can safely play the 9 from Q9x. Restricted choice means that declarer only wins 1/3 of the time (while playing the 8 would have won 2/3 of the time). Suppose the answer to this question is that declarer should always play the 8. East, knowing this, must now always play low from Q9x - hoping that declarer doesn't have a higher x. So when East does play the 9, declarer will always lose (while playing the J would have always won). So if East knows what you're going to do, it's better to do the opposite. Next up is calculating the equilibrium for a randomised strategy.. or I may read the Bridgewinners thread first to see if I'm totally off-track :)

East discarded a heart on the trump.

Based on the tricks to date, you already know diamonds split 4-3. I would play the king, then the jack. If we duck the first round, we have a straight 50-50 guess on the next round as to whether East holds the Ace or Queen, as everything is symmetric between those two options. Playing the king the first round therefore has to be better. East can play the 9 from T9x to give us a losing option, but there are actually no winning options to us inserting the 8; East having Q9x would be a Grosvenor. Edit - actually this isn't correct at all, since East playing x from Q9x loses if declarer can cover it with a smaller x.. hmm, that makes it trickier since the x matters.

2.5 years later, but I remembered you saying that when I happened to come across this thread today: https://github.com/socketio/socket.io/issues/2924 which was about how Safari *did* sporadically drop WebSocket connections when the page wasn't in focus, and a fix was put in place in SocketIO late last year. Might be of interest..

BBO requires a ping every few seconds to confirm you're connected. I'm guessing your phone is set to not allow BBO to keep running in the background.

If they saw the ♥A as a ♦A then 2♦ is understandable.

[hv=lin=st%7C%7Cpn%7CKarenAA%2C~~M489spyg%2C1parastoo%2C~~M210057w%7Cmd%7C3SAT83HKJ985DA3CJ6%2CSQ765HT76D9642CT4%2CSK942HAQDQ87C9875%2CSJH432DKJT5CAKQ32%7Csv%7Co%7Crh%7C%7Cah%7CBoard%201%7Cmb%7CP%7Cmb%7C1C%7Can%7CMinor%20suit%20opening%20--%203%2B%20%21C%3B%2011-21%20HCP%3B%2012-22%20total%20points%20%7Cmb%7C1H%7Cmb%7CP%7Cmb%7C1N%7Cmb%7CP%7Cmb%7CP%7Cmb%7CP%7Cpc%7CCK%7Cpc%7CC6%7Cpc%7CCT%7Cpc%7CC5%7Cpc%7CCA%7Cpc%7CCJ%7Cpc%7CC4%7Cpc%7CC7%7Cpc%7CCQ%7Cpc%7CS3%7Cpc%7CD4%7Cpc%7CC9%7Cpc%7CSJ%7Cpc%7CSA%7Cpc%7CS7%7Cpc%7CS2%7Cpc%7CST%7Cpc%7CS5%7Cpc%7CS4%7Cpc%7CH2%7Cpc%7CS8%7Cpc%7CS6%7Cpc%7CS9%7Cpc%7CD5%7Cpc%7CSK%7Cpc%7CH3%7Cpc%7CD3%7Cpc%7CSQ%7Cpc%7CHA%7Cpc%7CH4%7Cpc%7CH5%7Cpc%7CH6%7Cpc%7CHQ%7Cpc%7CC2%7Cpc%7CH8%7Cpc%7CH7%7Cpc%7CD7%7Cpc%7CDT%7Cpc%7CDA%7Cpc%7CD6%7Cpc%7CHK%7Cpc%7CHT%7Cpc%7CD8%7Cpc%7CC3%7Cpc%7CHJ%7Cpc%7CD9%7Cpc%7CDQ%7Cpc%7CDK%7Cpc%7CH9%7Cpc%7CD2%7Cpc%7CC8%7Cpc%7CDJ%7C&v3b=web&v3v=6.1.0]400|300|[/hv] I would have bid the same, I expect, and 3NT doesn't look like a great contract, though I'm sure others can advise on the merits of advancing with 4 spades or whether either player could have upgraded a bit more.

What does "cannot access" mean? Do you not see the Instant Tournaments button at all when clicking on Solitaire, or something else?

Yes, it bids 2NT with that hand when non-vulnerable, but requires 15 total points when vulnerable (eg add the king of hearts). If you swap the queen of clubs with the queen of diamonds it'll overcall 2♦; it seems with weak hands it bids its better minor. But add the queen of hearts and it'll bid 2♦. (Also, if the opponents compete to 2♠ it'll reverse into 3♦ with those weak hands, lol, so that's clearly a bug rather than a 'I'm only planning to bid one suit when weak'.)

+slow+ doubles it from 50 to 100. Permission sets it to infinite. But yes, it's definitely not obvious that these things are related (which is why this is the most-asked question on BBO!)

Check 'permission required to play'.

Side point. This works well when partner rejects, but what happens when partner accepts? When you were looking for slam this can be a bit frustrating, as it takes up a lot of space. In this example you're probably OK to continue with Blackwood, but that's not always suitable.. Should partner always be bidding 4♣ or 4♦ when accepting to show a control, rather than what is normally taught (just jump to game)?