smerriman

The number of times the favourable/unfavourable leads aren't really important - because of the way GIB is programmed to make the same lead in the same situation. That is, if you had 1 million people bidding one way, and 100 bidding another, the million would all receive the same lead - this doesn't meant it was 10000 times more likely; it may have been a 50:50 decision for GIB. Regarding the lead being poor, you'll need to read https://www.amazon.com/Winning-Notrump-Leads-David-Bird/dp/1554947596 which demonstrates the reasoning.

I can't quite follow the story. If you lead the Q of spades at trick 5, lose the K and A of spades and get a spade exit by South, you still have the jack and ten left to win the next two tricks.

3♦ is not a possible response to Stayman, despite the fact that GIB's description of it matches your hand. It describes a lot of impossible bids by trying to piece together different meanings. If my human partner responded 3♦, I would assume they didn't know how Stayman worked. (This isn't an attack, and you are perfectly within your rights to make such a bid with GIB; I'm saying you shouldn't make a bid just because of the description; you should make a bid based on how the system works / how you were taught Stayman). Ignoring that option, I would open 1♦ not because I wanted to show my diamonds, but because I would value the hand as worth 18 points, and thus is too strong to open 1NT, and the way to show a balanced 18 points is to open 1♦ and rebid 2NT. The fact this causes GIB's random simulations to pick a different lead is random. Next time those that opened 1NT will get the bad lead; or more likely, those that open 1NT won't be in game and I'll be making 3NT.

Yeah, have seen that a number of times, but not when a pass by partner convinces them to go from a 3♦ signoff to a 4♠ game!

Average number of tournaments you have to play before finding one with N deals you have seen before: 1: 3.3 2: 5.2 3: 7.6 4: 10.5 5: 14.0 6: 18.6 7: 24.8 8: 34.8

[hv=https://www.bridgebase.com/tools/handviewer.html?sn=Human&s=SAK6HT4DAT85CJ742&nn=Robot&n=S987HAKD7632CKT86&d=w&v=b&b=4&a=1CP1HP2HPPD(5-%20%21C%3B%204+%20%21D%3B%205-%20%21H%3B%204+%20%21S%3B%2014-20%20total%20points)P3D(3+%20%21D%3B%208-%20total%20points)3H(5+%20%21H%3B%206-9%20total%20points)PP4S(3+%20%21D%3B%204+%20%21S%3B%208-%20total%20points)PPP]400|300[/hv]

Yes, it's just standard GIB behaviour. If you had the diamond queen (probably "guaranteed" given your bid) instead of the club 4, for example, then which heart GIB plays is irrelevant double dummy. [hv=https://www.bridgebase.com/tools/handviewer.html?pc=n&s=sa4hat9daqt43cak9&w=s976hqj764d5cqt65&n=s53hk82dkj82c8732&e=skqjt82h53d976cj4&d=n&v=n&b=5&a=p2sd3spp3nppp&p=s9s3s8s4s7s5s2sacactc2cjckc5c3h5d3d5dkd7d2d6dth4ha]400|300[/hv] If basic GIB only does a tiny number of simulations, then once in a while all of them will be exceptions of the form above, and it will therefore choose a heart at random.

Wouldn't that be leb followed by 3S (or 3NT, depending on whether you have a stopper or not)?

Well, it's easy to see what happened - 4NT asked for keycards in hearts; 6S was then taken as a cuebid. Makes no sense to have it as a cuebid; but it also doesn't make much sense to bid that way either.

GIB1 0 - 0 GIB2

Indeed - if broze manages to jump above GIB, then ranmit would get knocked into 6th place in the process. I have set up the table for Round 2, pending the last qualifier. Feel free to start - playing one extra challenge against those you haven't yet challenged. For those who have two GIB challenges, the challenge you play first will count against GIB1; the challenge you play second will count against GIB2. Also, congrats cherdano for such an impressive performance! That must be a challenge event record by a long way.

We've reached the tentative deadline with 5 matches still to play: broze vs ranmit diana_eva vs zupey and three challenges by Gerardo. I've messaged him a couple of times without hearing back, but I'll extend the deadline by a few days in order to get them completed - they do have quite an important bearing on the outcome, so would prefer not to have to decide them.

You should check out the scores of the current forum challenge event.

[hv=https://www.bridgebase.com/tools/handviewer.html?s=SKHKJ82DKT5CAQJ87&w=SQ64H976DQJ87CK32&n=S98732HA43D963C65&e=SAJT5HQT5DA42CT94&d=w&v=n&b=12&a=PP1C]400|300[/hv] Where would you end up if East annoyingly opens 1♣?

If everything up to the point in question is completely identical, GIB will act 100% identically, unless one person has rented an advanced bot and the other one hasn't. (Or potentially if the other table has two humans playing against two robots, in which case GIB may interpret the human bid differently, even if it is the same bid).

How would this be coded? If you use the normal logic, a lot of the hands would accept a trick 1 claim..

Wow, 32%, that's huge. Oh wait, it's only 8 cents. Really, BBO has every right to increase the prices, and I'm sure they put a lot of thought into it.

I find that pretty strange - the hand is worth 17.9 points according to K&R, and you want to describe it as 12-14 without 6 hearts? Rebidding 2NT seems much better if you don't mind giving up a potential heart fit. If you think it's worth less, then opening 1NT seems closer than a 1NT rebid.

Ugh, sorry. Excel Online has a very annoying habit of accidentally overwriting a cell when trying to search instead.

GIB does stupidly lead 4 from 754, which is probably the most likely holding for West given sims prove passive leads work better, after which a heart is sometimes a trick better than a diamond. But obviously, a diamond should still work better on average - unless there was a fluke in the sims which caused the other scenarios to never come up.

The news article is about BBO tournaments, not ACBL tournaments.

Agreed, that is simply incredible news.

Yeah, I was saying you can distinguish them (make sure you know which robot in the scoreboard you are playing in each challenge / where the score should be entered) based on the order you play the challenges. Several people may not have $BB accounts set up.

Simplest option is just that your first challenge is against GIB #1, and your second is against GIB #2.

Thanks, that's really useful. Of the two approaches (bidding 3d with a minimum, and needing extras), both my partner and I could see major downsides in the other's approach - but it seems good/bad 2nt allows you to have the best of both worlds.