sieong

Most denial cue-bidding methods that I know of involves some kind of assumptions regarding relayer being able to tell apart holdings that responder may have (a classic one is AKQ vs none). When Adam and I were playing TOSR in the 2000's, we used the version documented in http://www.bantha.org/~pahk/bridge/tosr/, for which the primary post-shape relay is based on controls and it makes a number of assumptions as well. My experience is that it was reasonably efficient, but not as efficient as QP + PCB. I believe that methods based on controls followed by DCB tend to rely more heavily on assumptions as otherwise it would be too difficult to get to the critical queens before the auction goes past 5♦ (by which stage most of the time we cannot stop below slams). I have no experience playing KK relay, but from the posts that Kit wrote on bridge winners, I found that for many of the hands he showed, a small change of the relayer hand would have resulted in difficult guesses. All methods (as long as it uses assumptions) will result in some guesses some of the time (and without assumptions it may go too high too often). My subjective belief is that the assumptions made in KK relay were on the overly-loose side, and I think this is a question that could be objectively evaluated through simulation. Taking the example Nick wrote, say if opener hand was instead: ♠x ♥AQxxxx ♦AKQ ♣Axx and responder's possible hands are: ♠AQxxx ♥xx ♦xx ♣KQxx vs ♠Kxxxx ♥Kx ♦xx ♣KQxx I think opener would end up with a guess under KK relay while most other methods I know of would be able to tell them apart. As a side note, I think most methods would have a hard time separating ♠Axxxx ♥Jx ♦xx ♣KQxx from ♠Axxxx ♥xx ♦xx ♣KQxx so it is really down to the fractions of auctions that the methods could get right.

You may want to take a look at the Swedish club system as played by Fredin and Lindkvist between 2000 and 2004, which combines relay with a two-way club. Most of the relay sequences are explained in the notes. I believe it should be possible to adapt this to a Polish club base. [1] Front of card: http://info.ecatsbridge.com/systems/2003BermudaBowl-Monaco/Sweden/fredin-lindkvist%201.pdf [2] Back of card: http://info.ecatsbridge.com/Systems/2003BermudaBowl-Monaco/Sweden/fredin-lindkvist%202.pdf [3] Notes: http://info.ecatsbridge.com/systems/2003BermudaBowl-Monaco/Sweden/fredin-lindkvist%20notes.pdf

Yeah. The benefit of being able to resolve complete parity lower must be weighed against the cost of not being able to sign off opposite some combinations of honors as low as classic PCB. This can likely be answered by a simulation. I suspect there may be gains when combined QP is greater than 19, since typically the 5 level is safe, but may be a loss when combined QP is less. To answer why this particular ordering (I know it looks like madness, but I promise there is some method to the madness, and for sure there is plenty of madness in the method): the packing is meant to be xor. First step is all odds, or longest suit has different parity; second step is middle suit has different parity, etc. As to why... When opener has a suit with all three honors (not in responder's longest suit), the complete parity will be known right away for the first two steps. Also, in cases where responder has a short suit, if one assume the short suit had even parity (usually a good assumption, so this is good for "guessing scenarios"), complete parity is also "known". One trade-off here is whether knowing a bit about all three suits, or knowing one suit fully is more useful. I do not know the answer. Again it may be combined strength dependent. On the example hands in the forum, it appeared that knowing one suit fully is more useful., but sample size is too small. Fwiw, an alternative I considered look like what David proposed. As to Zel's point on Fibonacci series: there are indeed several ways to pack the combinations, which opened up opportunities to optimize for secondary objectives, for example, stopping as much and as often as possible. Fwiw, first step can have at most have 8 possibilities, any more and we will spill over in steps. There are almost for sure better ways to pack this. Also, the assumption that all parities are equally likely is almost surely incorrect, so if one wants to optimize more, there are lots of room. As an aside, it is pretty straight forward to extend this to answer more questions. For example, the 5th question could be the IMprecision resolution ask. However, since that question is not always present, I think on average is better not to pack it together. Another possibility is to use the 5th question to clarify interior quality (JT9) of the longest suit. As another aside, opposite three suiters, it may be better to go straight to the three long suits first, then answer parity on the short suit last (and invert the step for extra optimization). Anyhow, the post was mostly meant as a thought experiment as to whether it is possible to rearrange PCB to gain steps. Plenty of evaluation, especially on cost-benefit of not being able to stop as often, remains to be done.

EPCB. 4♦ - 4♥ (even ♠) 4♠ - 5♥ (even ♥ odd ♦ odd ♣) At this point this converges to classic PCB, but one step worse.

EPCB. 4♦ - 4♥ (even ♦) 4♠ - 4n (all odds, or ♥ is of different parity) [1] 5♣ - 5♠ (even ♠ odd ♥ even ♣) Honor structure resolved. [1] possible parities are ooeo oeeo eoee, which are ♠K ♥A ♣K, ♠K ♥AQ ♣Q, ♠K ♦AQ ♣Q, ♥A ♦AQ.Seems like EPCB is worse than classic PCB for determining slam. In particular, opposite the second combination, we may be forced to play 5n, which is inferior.

EPCB. 4♣ - 4♦ (even ♥) 4♥ - 4♠ (all odds, or ♠ is of different parity) 4n - 5♣ (odd ♠ odd ♦ odd ♣) 5♦ - 5♠ (♠Q ♦K) Honor structure resolved.

EPCB. 4♣ - 4♦ (even ♠) 4♥ - 5♦ (even ♥, odd ♦, odd ♣) Honor structure is resolved at this point, although 5♥ will still be asking KQ resolution in the minors. FWIW, my intuition on the four questions are same as Adam. Regarding J asks, there are more efficient structures, at the cost of not being able to stop as low compared to classic PCB. There has been less than 50 J asks in our partnership if memory serves right, and we have probably played maybe 5k hands together and bid another 10k hands ... so I would probably avoid optimizing for that.

EPCB. 4♦ - 4♥ (even ♦) 4♠ - 4n (odd others or ♣ parity is different) 5♣ - 5♠ (even ♠ even ♥ odd ♣) Unresolved between AQ in ♠ vs ♦. Same is true for classic PCB. Note that classic PCB would have resolved at 5♥, so EPCB is worse by a step. Had there been a pair of relevant suits for the final ask, EPCB would have gained a step.

EPCB. 4♣ - 4n (odd ♠, even all others) 5♣ - 5♦ (♦KQ) Honor structure resolved.

EPCB. 4♣ - 5♥ (odd ♥, odd♠, even ♦ even ♣, ♠K + ♥Q) Honor structure resolved.

EPCB. 4♣ - 4n (odd ♠, even all others) Honor structure resolved.

FWIW, if the only goal is to resolve honor structure as quickly as possible, the following (untested) structure is more space efficient than classic PCB, assuming the parities of the shorter suits are equally likely to be odd or even (to be validated; I have not got a chance to run a sim. If not true, there are ways to optimize this further). It gains on average 3/8 of a step, and can be made never worse than PCB on any honor parities assuming we always want full resolution. NOTE: I am not suggesting that one would play this, since it is unclear if it allows as easy a way to get out opposite the wrong honors as classic PCB. Full resolution is not the only goal for honor structure relay. Resolution rules: Longest to shortest, tire broken by rank, highest to lowest All suits are scanned Step 1 pretty for first suit Next question is an ask across all the remaining suits at the same time, answers in parities for these three suits are ... ooo, eoo, oee ... oeo, eoe ... eee ... ooe ... eeo Final question: same as IMprecision This may look a little abstract so I will bid the hands as examples. I will refer to this as EPCB in the posts.

I thought the topic of comparing different scanning methods came up before, and Richard (hrothgar) has a series of threads where folks compared different scanning methods. Going through the archive, it seemed like there was no consensus? Fwiw, I have been considering a different approach to simulate the outcome, so as to remove the subjectivity of such exercise. I will try to post the idea once it is fleshed out some more.

I find this new format a lot of fun, and a great way to introduce new players to bridge without the burden to learn about conventions and treatments. Kudos to the staff at bbo for innovating on tournament formats.

sieong - broze Segment 4 19 -35 http://webutil.bridgebase.com/v2/tview.php?t=ARDCHALLENGE:22fd73fa.7b95.11e7.b67e.0cc47a39aeb4-1502126612&u=sieong Well played, broze. Congratulations!