allfail

Today in a best hand tournament, in the last board I played, I had something like 3-6-1-3 and 13 points or so I opened 4H. my RHO overcalled 4S, I doubled, my LHO changed to 5D and I doubled again. My partner led a small club. I had clubs K86 in my hand while on the table it is AQx. (x being something like T or 9.) When table played the x, I intended to play K but was unable to do so! The program just let me choose between my 6 and 8.... I was using the web client btw. So I just waited there until the time is up. I should say, I did wait for at least more than 10 seconds, so it is not something happened just right at the time the tournament ended.

Dunno if this fits the right section, but I think it is an interesting idea to have a different reward ratio and would make people want to play $5 a lot more since it would be a lot easier to win. In the current setting, the $1 and $5 best hand plays quite the same, except maybe the field is tougher in the $5 ones...

the rule being?

problem being?

I think I open my suit openings are similar to yours. I think invitational openings are not necessary under all vulnerabilities (at least for me) since I don't like to play edgy contract and spend a lot of time or end in a partial. For those better hands partner would also open if you didn't. However, I don't know about 1NT. My rule has always been open all 16+ if vulnerable. So if a hand does not fit in your previous description yet has more than 16 pts I would open 1NT. This includes 5M332, 5M4m22.. etc. Nonvul I would do the same first/2nd seat, but more depending on my mood. I think it is a good thing to discuss whether one should open 1NT in best hands. The downside is of course, being leaving out in a partial or being heavily penalized. The plus side is to reach game, with the bonus that GiB sometimes misdefends if you bid 1NT with 5 of a major. In my personal experience, I think ~1/2 or maybe more of the hands would reach game if you open 1NT 1st/2nd seat. The other half you would land in a partial, and the score is often small and can be played reasonably quick. It is very unlikely to go down a lot or being doubled unless opponents have game. In this case either way you are going to be negative. To sum up, I think having a 1nt hand 1st/2nd seat can score 200-300 in average if you open and is slightly too good to miss. Also, maybe the most decisive factor is that if you don't open and opps do, you are in a horrible situation since you cannot compete for the contract and they tend to play in a partial horribly slow.

My web BBO indicated that my recent total point tournaments (which are almost all best hand) averaged around 4200. I think I almost always get 18 or 19 boards played every tournament. The total number of boards range from 20 to 30 though. My lowest score is in the negatives and highest score is no more than 10000. Anybody want to share the results?

Hmm, that is quite interesting. Evidently I misunderstood something. So it is most commonly played that a new suit after XX promise nothing? I can understand the logic if this is the case. But I thought it is similar to a takeout being covered by a suit-- here there's no doubt that he can pass if he has nothing. I think in my previous posts there is one which I described more or less the same problem after a new suit instead of XX. Anyway, now that I know 1D promises nothing I won't be bidding 5D in this auction next time.

Non-vulnerable, sitting south, east opens (1C)-X-(XX)-1D; (2C)-2H-(3H)-p (3S)-5D-p-6D X-ap GiB N had the hand Qxx x Jxxx QJxxx. My hand is Axx AJTxxx KTxx --. 1. Can GiB somehow pass with this hand after the XX? I admit technically he had the bid but this bid presumably is made usually for much better hands. 2. I did overbid, but I like my chances of making 5D opposing AQxxx diamonds so I bid it. Now GiB, certainly enough, thought 5D meant 29-30 points and raised to 6. This problem has been discussed so many times. Why there is no fix? There is no such bridge logic saying he could raise to 6 with his hand. He is sub-minimum of his bid already; if I had 29-30 points I would bid 6 myself since I saw his free bid after XX. 3. In general, I feel recent versions of GiB has poorer slam bidding skills. It is somewhat more slam-aware but those jump to small slam very often results in a slam lacking two aces where he certainly has an RKCB bid available. Sometimes it is even worse; the contract is just so far off. In those cases I can see there might be a hand fitting my bidding which can make the slam makeable but for an average hand of the bid it is rather a long shot. It seemed to me in the earlier versions of GiB he didn't jump as recklessly and once he jumped the contract is usually of reasonable playability.

first seat both-non I opened 2C. The bidding goes 2C-2D;2NT-3NT;p(4D)! I doubled and collect 1100 easily. GiB held Jxx Qx KQxxx Axx. This is the second time for me seeing this happening. In my opinion, this must be the result of some huge sampling error of the sampling algorithm. It seems very likely that GiB just deals a fixed number of hands and uses those satisfying the bidding constraint to determine it's action. I can see with this holding of his the number of valid sample deals would be very small and the response is erroneous.

Yeah I understand your point. It sort of depends on your goals though. As far as I can conceive there are many situations where GiB would have a bid which does not match its descriptions but works nevertheless. Sometimes there are no plausible choices sometimes there are other perfect bids. For me, it doesn't matter whether gib conscientiously psyches or it just thinks some bid works best, as long as the simulation was performed correctly (in my current understanding it is a big if however). It should be a strength of AI since we humans can't do such things in a short time and if the simulation is correct it should lead to a better result.

What it meant is that GiB can psyche and it is fine, why do we have to fix this?

Another board GiB had: S AKQJx H ATx D x C Jxxx South dealer Bidding went 1D-1S;2H-2S;3NT-7H! My hand is Sx H KJxx D AKxxx C AKx What is GiB doing? Arigreen, did you change GiB's slam bidding strategies? I think recently I experienced a lot of this kind of reckless bidding compared to before...

Siting opposite a 2NT opener, GiB held S Qxxx H Q D AKxxxx C KJ The bidding went 2NT-3C;3H-4D;5D-p! My hand was S AK H AKxx D Qxxx C Axx Shouldn't GiB bid 6 at least since we have at least 35 HCP? Also, under this kind of circumstance I can't think of other bid of mine... (4NT is RKC, but I don't know his strength, 4D is stated to be 7+ HCP and who knows GiB won't pass over 4S or 5C...)

I think the natural way would be that 4H is a minimum hand with support (without an ace, no void, 5- HCP etc) and 3H is a forcing support.

I've never seen this before either. I had S KJ H AKQJxx D KJ C Axx The subsequent action was: 2C-2D;2H-3C;3NT-5H; And I passed since I don't understand what GiB was doing. If the bot saw me play he should be more aggressive since I am passing with opening values all the time! :D

Thanks, Cascade. It is quite interesting to note that if we look at the renormalization of the probabilities, say the 37 count, it shows a ~10% difference, which means the tied highest HCP deals occupied 10% of all the dealt hands! Of course not all of them would be bad for you (roughly 2/3 of them is bad), and this amounts to 1-2 deals every tournament, surprisingly confirming my estimate. So here's something I'd like to ask: is it possible to change the dealing method of those besthand tournaments to the deal-and-rotate method? I just think that "whenever you get a 15 count or below you would be facing an anomalous high chance of somebody who has the same HCP as yourself" is not a very welcome thought. Besides there's strategic inferences. I always think that there might be a way to setup GiB and double their contract to gain points. Knowing the distribution this way might slightly favor this approach when one have some 12-15 count perhaps...

GiB held S Qxx H xxxxx D Axx C xx After 2C-2D; 2H he chose to bid 3C alerted as double negative...

Yes it is indeed very confusing (at least to me) and I did think it is the same for a long time. But in the end (1) will have S average 14.85 points and (2) will have S average 15.1 points. The reason is that in algorithm (1) you are less likely to discard a hand with 10-12 points than discarding a hand with a higher point count. Or to put in other words, the two distribution would be identical if (1) picks up any board distribution as often as (2) does. However, in the boards with the highest HCPs tied (1) is more likely to pick them up.

How does GiB simulate your response after the double? If it simulates it properly it is quite something to know that simulation wise this decision is that close.

To my own defense, my number was never off more than a standard deviation so even the not-so-good random generator works ok. In fact, what I changed was just from using the global random number to newing a class member in the RandomLib. I don't really know the difference between the two. But as so much as that it is the only perceptible difficulty in writing such a dealing program. In addition, I hope I did present all the necessary details of what I did in this post so the "obvious" differences in the result between the two possible ways was not really obvious to all the responders on this post and you may be the only exception. If you think this is obvious why don't you be so kind and let us know instead of just replying a "nope"? I acknowledged that you verified the 44.3% percentage in previous posts but I just couldn't figure it could be the same person who just responded a "nope" up there. Frankly speaking, why not just bypass the post if you don't want to share your knowledge? On the other hand, strategy-wise these two method does have some impact. To begin with, we all recognize in a time-limited, total point game, the overall strategy would be to ignore as much partials as possible. Therefore, one might open quite heavily; for example, myself (previously) open only 16+ any shape any vul. and 19+ when nonvel, 3rd or 4th seat. This action can be interpreted as choosing to open with a threshold of game possibility. However, why doesn't one just open when game is almost certain? The reason behind, of course, is that there is a cost of not bidding. The cost is not quite the time spending passout, instead is that every few boards even if you pass your opps might open. This, although mostly ending up in partials, costs a lot of time (maybe as much as 1.5 mins?) as GiB plays slower in partials. So to maximize the games in a given time period we have to open some number of hands provided that a game is somewhat likely. Now we compare the two distributions. Note in the current method you would have twice to thrice as many of those tied hands compared to the first method, in which if you don't open your opps might. This reduces the optimum threshold of game possibility for one to open. I am not sure how large an effect this is, but among 20-25 boards I played in a tournament I would encounter, maybe 1/4 to 1/3 of the boards to be in the situation that I want it to pass out but some opp opened. Factoring in that there has to be a tie for us to have a difference, it's maybe like 1-2 boards per round. I am not sure if this is an observable effect, but I do sense this kind of thing happened more often to me after the end of January... Is it even possible that BBO had changed the dealing policy by then?

Aha! Now I know why there is such discrepancy. In fact, dealing randomly and give the best hand to South is quite different from dealing and discard those which South does not have the best hand. The difference is subtle though, and that's why people (including myself) did not notice this previously. The problem comes in when there are ties: Imagine a layout of point counts. If the HCPs in all hands are different, then the accept rate (of the second method) is 1/4 whereas in the first method it is always 1. Now if there is a tie with two hands at the highest HCP then the accept rate for the second method would be 1/2, and vice versa. That is, the deal-and-throw-away-unwanted method has a higher accept rate for tied deals. But what point counts do the tied boards tend to have? They strongly tend to be weaker hands! For instance, a 10-count highest HCP board would always be accepted since every hand would have a 10-count and a 16-count board would be accepted only with a chance everslightly higher than 1/4. This in total results in a ~0.3 point difference in average, and ~2% chance of having a total of 24 HCPs or more as I have also checked the numbers with the second method. Now that we sort this out, it is clear to me that BBO uses the deal-and-throw-away method. It should be stated clearly somewhere as there is a real difference. I thank those who suggested me to look at previous records since they can't be sure about the details in my program and thus my trustability. However, for those who suggests a program like this can go wrong in many ways I think they should either check their own programming ability or stop their ignorance.

For example?

Now I am getting really confused... anyone wanna help here? I stabilized my random generator now it is working properly. The produced result always lies within the expected standart deviation. However, the number I got is 15.11+-0.002 for the best hand and a 45.98%+-0.05% chance to have a combined HCP>=24. My program is really simple. It just deals the 16 spotted cards to the four hands with probabilities proportional to the "vacancies" left in the hand. Then I chose the hand with the most HCP as the best hand and another random one as its partner.

While I agree generally with the comment, in light of the fact that we have 52 different cards in a deck, having any one of them being out of 2 standard deviations is actually quite normal. However, if you always choose to watch, say how many Aces you got in average, then the number would "usually" turn out to be much normal.

It is not as easy as it seems to calculate this probability exactly... Nevertheless, if we have an ideal random distribution it should be very accurate to just simulate it by dealing a lot of deals. In particular, by the calculation above one should expect the standard deviation (error bar) of the percentages above is ~0.05% for a million effective deals. (For arigreen's method it should be 250K effecitve deals and the error is ~0.1%). Therefore it is actually an interesting thing that we get so different answers. I checked my program and didn't find any bugs, but the answers got from a million deals seems to vary too much. One of the possibility is that my random generator is cycling and I might have to reseed after some number of deals. Still, my expectation value is at least 45.9% (the least number I have seen for a simulation size larger than 10K) so we are still not consistent. I am using the open source randomlib for generating random numbers.