Wwchang

Seconded. I use Double Dummy Solver as well after playing a session's worth of boards to analyze, and this is completely broken now. It would have been much better to restrict access only to the tournament info (if that is truly needed) than to put everything, including boards with no need for protection, behind a login gate.

I have a basic question that I can't find the answer to easily. After, say, 1♠ - (P) - 4♣ - (X) - ?? What are the standard meanings of the responses: P, XX, 4♦/4♥, and 4♠? I assume 4♠ is minimum with no slam interest, 4♦ and 4♥ would be control showing and denying club control. What are pass and XX? Does one show 1st round control, and another show 2nd round control, or is one of those bids neutral and give partner the opportunity to show a control? By extension, what are the meanings of partner's bids if I pass and the auction rolls around to her: 1♠ - (P) - 4♣ - (X) - P - (P) - ?? Does XX show a second round control, 4♦ and 4♥ guarantee 1st round control? Thanks!

I think it depends. Bidding system is relatively unimportant, but I think bidding judgment is quite important: making 200 when the other side is making 420 is no good, and if you make a poorly judged sacrifice, then particularly at MPs there may be no difference between -300 and -500. I would be shocked if Spingold top seeds do not have significantly better bidding judgment, on the whole, than Spingold bottom seeds. (Whether that superior bidding judgment works out in a particular sample of 64 boards is luck.) One partner of mine (an intermediate), whose stats I've tracked through 800 cross-IMP boards, loses on average 0.57/board on bidding (0.37 of this is competitive, 0.12 is non-slam constructive, and 0.09 is slam bidding), 0.30/board on dummy play, and 0.12/board on defense, compared to "sound" play (which is limited to my skill in the post mortem, aided by an engine); I look at each play and try to determine whether it is reasonable, even if it does not lead to the double dummy best result. I don't track what could have been done with a different system, so these are all related to misjudgment. I am sure that there are additional errors that I don't pick up in my analysis, probably in the range of 0.2-0.3 imps/board in total. This also does not include any errors that end up not costing actual IMPs on the particular board.) So at least for this individual, working on improving bidding judgment would appear not to be time wasted. Errors are errors; they can all cost. At least in my set of stats, the average bidding error cost 6.9 imps, the average dummy play error cost 4.7 imps, and the average defensive error cost 2.7 imps.

During the US trials, a hand came up (can't remember which; I think it was in one of the Diamond matches) where a 3S bid was made, and commentary appeared speculating that this was a nonserious 3♠. How does this work? In Fred's "Improving 2/1 Game Force" articles, he has an example in which the trump suit is hearts: EXAMPLE 5: ♠Kxx ♠Qx ♥AJxxxx ♥Kxx ♦xx ♦AQxxxx ♣Kx ♣AQ 1♥ 2♦ 2♥ 3♥ 3♠ 3NT 4♣ 4♦ 4♥ Pass He writes: "When hearts is agreed at the 3-level, opener must bid 3 if he has a control in spades. Any other bid would deny spade control (3NT would be Serious with no spade control)." It's now been some number of years since this came out. Is it now common to treat 3♠ as being the serious/non-serious bid when hearts are trump? (If so, I assume 3NT becomes the cuebid for spades, and therefore a direct 3NT confirms/disconfirms serious slam interest while showing a spade stopper.) Is there a view on whether using 3S here as the serious/non-serious bid is superior to making a mandatory cuebid of a spade control in this sequence regardless of slam interest? (Assuming you've decided to play S/NS 3NT generally.)

Poker is inherently easy to watch. The player has a very limited number of options at each stage, and the cameras showing the hole cards add to the drama. Chess is virtually unwatchable in a meaningful way, except to experts. Most of the likely spectators are not going to be appreciate why Radjabov's positional "blunder" changed his evaluation from +0.21 to - 0.35 and see the continuation that will lead, 20 moves later to a lost endgame. More likely, they will just count pieces and think he's still up because he has one more pawn in material. At the Super-GM level, one move blunders are very, very rare. So the best that 99%, probably 99.9%,of the audience will really be able to do is to watch the engine evaluations. That is somewhat interesting, but hardly compelling. Even Maurice Ashleys "exciting" commentary doesn't change that. Blitz is even worse to watch, from a substantive point of view. But a 7-hour classical game is also not compelling. Bridge is in between, but much closer to poker - anyone who knows the rules and is an intermediate level player and is watching double dummy can see and understand when a play is about to fail. They can also usually appreciate a difficult play in a way that they are not able to grasp why Kg6 is the only drawing move but Kg7 leads to a loss. (They won't appreciate a defensive return that breaks up a squeeze, but overall I think it's much more comprehensible to amateurs than chess is.) As far as compensation, I read an article at some point that indicated earnings probably drops to about $200k if that for the 10th ranked player in the world. Pretty sure it drops very rapidly beyond that. The big money is in the WC matches; super tournaments pay reasonable appearance fees and prize money, but they all invite the same (generally top 10 players plus a few locals), and everyone else struggles to do well in open Swiss events that they themselves pay to attend, and for which prize money is not that lucrative.

I think what you are seeing is that experts just make many fewer dumb mistakes than the rest of us. Note, however, that may seem like a "normal" play to an intermediate or advanced player will often be a clear error to the expert (although maybe the advanced player will see and understand the mistake in the post-mortem). In addition, the expert will also give away less information through tempo and through carding than lesser players. Experts also have better bidding judgment, which may not show up as "errors," but on borderline bids that are 60/40, making the right judgment adds up over time (here, I am talking about situations where the suboptimal bid does not appear unreasonable). At the margins, they will also have greater technical skill in play and bidding, but something like a compound squeeze or the opportunity to use a deep fancy convention comes up sufficiently rarely, that I doubt these add up to more than 0.2 imps/board in the long run. This doesn't fully explain outlier pairs like Meckwell, but I think accounts for 90%+ of the difference between an intermediate+ pair that averages 50% and a "normal" expert pair that averages 63%.

on 4♥ contracts specifically, DD tricks averaged 10.01 and actual tricks averaged 9.99 over 8699 contracts. DD made 68.65% of the time, actual made 68.35%. The difference is much larger for 3♥ contracts. There, average tricks were 8.41 DD and 8.49 Actual, with 3♥ making 52.82, and only 48.46 DD. http://www.rpbridge.net/9x29.htm

I have some calculations on the other thread that suggest that blasting is about as good as random acceptance of invites, but if acceptance of invites is better than random, then inviting leads to a better overall result (caveat: does not take into account opposition bidding, and the simulation that was run does not exclude superaccept-type opening hands).

I'd tweak this a little bit. I put this together (I don't know how to make the table look nice): ..........................Invite.........Diff....IMPS...Weighted ................Blast.....Go.....Stop....on stop.stop....IMPS 6....39..0.0039.-400.....0.......0.0039..100......3.....0.0117 7...330..0.0330.-300.....0.......0.0330..100......3.....0.099 8..1639..0.1639.-200.....0.......0.1639..100......3.....0.4917 9..3830..0.3830.-100.....0.1915..0.1915..240......6.....1.149 10.3358..0.3358..620.....0.1679..0.1679.-450....-10....-1.679 11..769..0.0769..650.....0.0769..0.0000 12...32..0.0032..680.....0.0032..0.0000 13....3..0.0003..710.....0.0003..0.0000 10000 What I've done is to assume the quality of the invite as x% making the right decision on borderline hands. I'll assume that on any hand where game is -2 or more, the invite is always rejected, and where game is +1 or more, it is always accepted. So on the borderline hands (making 9 or 10 tricks), the the invite will be accepted on x% of the hands that it makes game, and rejected on x% of the hands that it goes down 1. The table above is for x = 50 (i.e., no better than chance, unless 8 tricks or more, or 11 tricks or less). It shows inviting would be worth 0.072 imps/hand. The one-trick difference when game goes down 2 or more turns out to be pretty costly for blasting to game, eating up all the advantage of the 10:6 bonus for going to game. If your invite acceptances are better than random, we get better results for invite: 55: +0.355 imps 60: +0.638 65: +0.921 70: +1.204 75: +1.486 80: +1.769 85: +2.052 90: +2.335 95: +2.618 100:+2.900 Of course, this doesn't take into account E/W bidding over 2H or 3H. I don't know what a reasonable accuracy percentage is, but maybe 70%+.

Separate from this question, is the question of how well double dummy results compare to single dummy results. At least in the case of 4!h contracts specifically, Pavlicek's stats suggest they conform very closely.