sfi

Well spotted.

I don't have the auctions at the other table, but it looks like 13 IMPs were due to the hands being declared from the other side and getting a different lead. Systemic differences appear to play a part in both cases (the big swing came when declarer had to guess which king to finesse for and I had led low in one of those suits. At the other table the other hand had a safe lead and declarer misguessed). Another hand cost 13 IMPs when declared from a different side. Here also the play at trick 1 gave away the contract, but that one was defender error rather than who was declaring. Different leads from the same side also directly resulted in 13 of the IMPs. Only 1 of those might have been affected by the auction. So 39 IMPs were decided at trick 1, and 1/3 of those are due to differences in system. The other play decisions were unaffected by any bidding IMO.

Win the SJ and lead the D10 intending to finesse. This line looks like it guarantees the contract. If either opponent has 4 diamonds, I pick up the suit and take 6 diamonds, 3 spades, and a club. If East wins the first diamond I can only lose 3 hearts (I duck East's first honour and cover their second card) and a diamond before cashing my 9 tricks.

Playing any reasonable system, having good agreements is far more important than what those agreements are (my guess would be at least a factor of 10). If you assume both pairs have reasonable agreements, then the majority of the points are likely to come down to declarer play or defence. For one useful data point, I took a look at the final we just played the other night. All 8 players are competitive in national events and several have represented Australia, so the standard was pretty good. Over 28 boards the score was 61-40, and it turns out it's clear how to attribute all of those IMPs: Declarer/defence: 57 Bidding judgement: 27 System differences: 16 Psyche: 1 Since defence and declarer play are intricately linked, it's quite hard to separate the two, but that sort of breakdown feels pretty normal. It's also hard to separate swings that should be attributed to a better system than those properly attributed merely to a difference in system (my view is that all 7/16 was due to a misunderstanding and the other 9 to hands that just happened to work better for one pair). It's worth noting that all the double digit swings came from games that were made at one table and set at the other - mostly due to difficult defensive decisions or defensive errors. Looking just at the swings doesn't necessarily tell the whole story, but it's an easy first approximation.

I don't know what the actual value is, but the longer the suit is the more likely it is that West will bid. Surely it's below 5, and you're right that it may well be above 4.5. I would be quite surprised if it's more than 4.7, but I'm happy enough to accept a value someone else works out. 4.5 makes any table estimates easier though.

The problem with your analysis is that you are assuming that the choice of suit is random. but it's not. I haven't worked through the author's arithmetic, although he's normally spot on. However, start with the assumption that opening leader will normally lead their longest suit unless there is a compelling reason not to do so. Therefore, when West leads a spade, we assume that they have at least 4 cards in the suit (the average will be somewhere around 4.5). Once we find out that West holds 5, it really doesn't change the probability of holding any other specific card all that much. And if we find out that West has led from a 4 card suit, it increases the expected length in the other suits and makes it more likely that West holds the CQ than East. In short: - We know West has length somewhere, and we will find out where on the opening lead. Chance of holding the club queen is approx. 50%. - We happen to find out it's in spades. Chance of holding the CQ still approx. 50%. - If we find out that West holds longer than expected spades, chance of holding CQ < 50%. If West holds shorter than expected spades, chance of holding CQ > 50%. Distributions in other suits are more likely to affect the odds, but again it's not straightforward. If, for instance, we find out hearts break 3-4, that's pretty much expected. Since West chose a spade rather than a heart, we can estimate their heart holding at around 3 if seven cards are missing. If we find out they are 2-5, then that would change the odds. To summarise, vacant spaces is a good theory. But there are caveats to how it is applied, and those caveats can be tricky.

Or who I'm playing against. :)

Not raising hearts is, shall we say, odd.

I'm not that crazy about forcing to the three level on this hand. 1♥ for me.

Indeed - one can pick up all sorts of information from opponents' flickers. Last week I held a hand very similar to this, where LHO overcalled in my singleton at the one level. RHO thought about something and I decided to pass despite it being a clear reopening double situation. Problem was, they now got to play in their 26 count game at the one level. Lucky? Undoubtedly, and I am likely to double next time even with the flicker. But I would have a real problem if they now received a favourable adjustment after they were the ones who both stuffed up and passed extraneous information. If this becomes a mandatory double situation, the skill of reading your opponents is significantly reduced. Apart from all the other points that gnasher brings up, this approach is dumbing down the game to try and achieve something fairly negligible.

Reasonable as far as it goes. But there is no reason to deny partner the chance to investigate further by unilaterally setting the contract. 4♠ for me, with a fallback position of bidding 6♣ later if partner doesn't so anything interesting.

In Australia, a 2♣ response to an opening 1NT is never alerted. It's defined as 'self-alerting', just like doubles, redoubles, and bids above 3NT (except for opening bids). There is no concept of announcements in Australia, although it may be introduced in the near future.

Your system isn't clear here. Is 2C forcing to game? If not, then West needs to bid something more than 3C, and 5C shows some extras. If so, then 5C shows a minimum hand with nothing interesting to say and is simply wrong on this hand. I don't think much of 5C in either case, but they convey significantly different meanings in the two cases. As to what West should bid, a splinter looks spot on - especially if I can bid it below 3NT. I am likely to continue with 4C if partner does sign off in 3NT, but at least partner has a good picture of the hand at this point.

Having skimmed through the Bridgewinners thread, it sounds like the available information is that: The Israeli team requires their government to approve the travel. The Israeli government requires additional information relating to security. The Israeli bridge federation asked the Indonesian bridge federation for a suitable contact. No contact was provided. I may have missed some of the discussion, but it seems to me that the WBF should have been heavily involved with facilitating this request. Leaving it up to the individual federations seems inappropriate for such an event. Why is their role not being more heavily scrutinised? Or do I have the essential facts wrong?

This just goes to highlight regional differences. In Australia everyone asks for an explanation on this auction because it is played so many different ways. We occasionally get pitying looks for our Neanderthal system when we reply 'simple Stayman, asking for a four card major but doesn't promise one'.

Not that I disagree with the general point you are trying to make, but '3NT makes easily' is rather an overstatement. Declarer can come to 9 tricks on the layout, sure, but it's not at all clear how to do so when dummy hits. For example, if the North-South cards are swapped declarer is simply down on a spade lead and in trouble anyway.

Nobody in this discussion is questioning the accuracy of BBO's deal generator. Interpretation of statistics can be a surprisingly tricky science at times though.

Turns out you can lead a horse to water...

I'm not convinced you have thought about what you wrote. At least one of these numbers is clearly nonsensical.

You can replay the hand at your leisure from the My Results section on the right side of the interface. From there you can watch the play one trick at a time by using the arrows below the hand.

Australians don't. The most common system bases are either Acol or Standard American in roughly equal measure. 2/1 and various strong club systems are each maybe played by about 10% of tournaments players. My understanding is that Acol is the most common system in New Zealand, but I doubt they would have an "official" system. Canadians play in the ACBL.

Does anyone play 5H in this auction as slam invite? Every time I have seen it come up it's just to play with lots of hearts.

Even though pass is not an LA, the 2NT bid still should be scrutinised. 3H at least is an LA in this auction, which could lead to real problems for E-W that are more likely to be avoided by bidding 2NT. N-S have misinformation, and this needs to be considered as well.

Indeed. Ruffs are, or were, much more gentile.

I added the caveat because I thought there might have been something about it in the rubber bridge laws once upon a time. Certainly Mollo's characters quote something along those lines, although that may simply have been writer's license.