xxhong

第四副牌还真开错了。５H是错误的，５H通常应该是７张以上，QJT（９）打头的套，边花没有输张。 KJT９xxxx在同伴拿了HAx 或者Axx的时候就丢７H了。 这种例子早年间论坛里就讨论过了。

It is possible that partner holds short D, here 5C is in jeopardy and 3S x is easy money. However, sometimes, partner can hold a weaker hand: Qx xxx Jx AKQxxx, you may only take 1C, 2D, 1H and opps can happily make 3Sx (or they misguess H, only down 1). Here, you may wonder why you didn't want to show your club support and land at an easy 5C. With at least 9 card fit in our side, after opps bid 3S by their own when red, I think partner is more likely to hold this hand than the short D hand.

I bid 3D only when this bid shows extra.

IMO, 3S just shows doubts in 3NT. The shape can be 3-5-4-1 (for example: xxx AKTxx AQxx x), 2-5-4-2 (For example: Qx AKxxx AJxx xx). I think with 1-5-4-3, I would almost always raise C, which is the purpose of 3C. If you can't raise 3C to 4C, why would partner bid 3C? Of course, there are other types of hands that you may have doubts in 3NT. Sometimes, your hand is too strong to bid 3NT. For example: Ax AKxxx AQxx Jx. Here, it feels good to bid 3S and pull partner's possible 3NT to 4C to show the slam interest. This also helps partner to evaluable his SKxx because if you bid 4C directly, partner may think his SK is wasted.

1C p 1D 1S 2C p 2S(gf, may have C gf hand or D gf hand) p 3H 3S 4C(it is a C gf, no S wastage and some slam interest) p 4D(RKC)...

This hand appears to be too strong for 2NT. With strong D suit, good controls, stiff A and 4 losers, I'd either open 1D and hope it won't get passed out, or just open 2C and rebid 2H with reg partner or 2NT with pickup partners or gib.

I think it is a good 13 plus a singleton with 6 losers. If you don't shown any signs of life here, partner may have a difficult time to decide whether to push more with marginal hands that makes a slam. The line I draw here is 15 points (high card points and distribution) to show the serious or non-serious hands (Or 6 losers). Perhaps it is lighter than many others, but not lighter too much.

Vanilla 2/1: 1H 2C 2D 2H 3C 3D 3N(nonserious 3NT) 4H 1H 2C 2D 2H 3C 3D 4D(serious cue) 4N(RKC) ... My 2/1: 1H 2C 2D(weakness) 2H(natural, may belong to 3NT, so let's see) 3C(D) 4H(stop) 1H 2C 2H(extra, D suit) 2S(2-3 H) 2N(2+C) 3H(3 H) 3S(cue) 4C(cue, even number of KC) 4D(cue) 5C(cue, extra,denies HQ, denies S control) 5D(cue) 6C(cue) 6H pass.

I think there are some misunderstandings. First, I am not unsatisfied at all about gib's progresses in recent years. I have been pointing out some of the problems that may be solved in the future. If any programmers feel insulted because of my comments, I regret. I believe my comments have never been pointed to any particular programmers in your company involved in this project. If you are unhappy about my comments on gib, I won't offer any in the future, because it takes a lot of my time.

Well, your experience probably just reflects your bidding accuracy in slam bidding area. There is a very important principle in grandslam bidding, bid the grandslam only when you can count 13 tricks (of course, doesn't have to be a sure way, but at least should offer a reasonable play for 13 tricks). I think many good players follow this principle. If gib always pushes to grandslam based on a simulation result that AJx and KTx gives 3 tricks, I call it a huge intrinsic design mistake. Now gib's bidding is so rough. The other day, I saw gib bid 4S with AKJxxx xxxxx xx - after p(gib) p 1D p 1S 2C(opp) 3S p and we missed a cold 7S (details could be slightly off, but the hand is real). Does the simulation help you? Also, it is a long know bug that gib doesn't really know how to proceed after a partner's splinter bid and often overbid or underbid. All these problems point to bad simulations are really the keys to prevent gib from sound bidding. Actually simulation is very powerful if you can supply good and intelligent constraints set up; large sample size; and careful analysis to avoid double dummy over optimistic evaluations. For now, I still see none of them have been done. Now, gib's evaluation tool is very limited. It doesn't have a sound loser count scheme to decide how high to bid with distributions. It doesn't have a sound trick counting scheme. All these stuffs should be carefully implemented to improve the performance, because human experts apply all these kind of evaluation techniques in almost every hand. Also, human experts do construct hands and simulate in difficult problems. After years, I still see none of them have been carefully implemented in GIB's code. Also, many bids are badly defined (or not defined) after 3 rounds of biddings. At least, such kind of improvement should be encouraged, not prohibited if BBO is serious about improving gib's bidding performance. It couldn't even make a penalty double against slam contracts with sure defensive tricks in many situations or fails to cash them after making a penalty double. The roots of all these problems are badly designed simulations and naive hand evaluation tools.

No Strong jumpshifts. Quite standard system with ERKC: 1C 1H 2C 2S(responder's reverse, gameforcing) 2N(natural) 3H(long H, denies C support) 3N(natural, H shortness) 5C(ERKC) blabla. Quite standard system without ERKC, with 4NT as RKC.: 1C 1h 2C 2S 2N 3H 3N 4C(cuebid, 3H denies C support, so must be C shortness) 4D(cue) 4S(cue SK) 5D(cue cue DAK) 6C(cue C void or stiff A) 7H My improved structure after 1C 1H 2C: 1C 1H 2C 3H(set up H, gf, I go through 2D with sign off hands in H or invitational hands) 3S(cue) 5C(ERKC) ...

Slam bidding, especially grandslam bidding, is almost always a matter of trick counting. It is never a matter of the simulation results. Accurate slam bidding can often place the most honors positions and the overall shape. I don't really think simulation can do the job. Now gib sucks big time at deciding how high to bid after 5NT K asking. Also, I am not only talking about slam biddings. IMO, at least most 3 level biddings should have accurate meanings, All the bids shouldn't contradict each other. It's never a matter of simulation. There are still many bids that lack of accurate definitions. For example: If system says: 1H 1S 2D 3C 3D shows 5+ diamonds, it would be absurd to bid 3D with 4 diamonds just based on a small sample sized simulation. All the cuebids should also have accurate meanings that provides important constraints to slam decisions. Those constraints would lead to successful trick counting. Simulation is so bad in so many ways. It doesn't know bridge is a single dummy game. Therefore if you have AJx vs KTx, it thinks that you have no losers and trick counting tells you that you have 0.5 losers. Also, how seriously you take opps' bidding into account is a difficult AI problem. If you take wrong constraints from opps, you can never achieve the correct bidding or playing results. Many times, I see opps' misbid leads gib to bad finesses in 100% contracts and go down. All such things can be avoided by easy trick counting or totally ignoring opps' bidding in 100% successful situations.

I hope this work will be extended to higher levels in the future, which is important IMO.

1C 2H (strong jump shift) 2N 3H(set up H) 3S(cue) 5C(ERKC) ....

Without any conventions, 5H seems good. With conventions, here I play transfers over 3NT, so it is a 4D bid to show 5H+6D. Over partner's 4H, I RKC. Over partner's 4S, I guess to bid 6D. Over partner's 5D, I guess to bid 6D. Over partner's 5C(a cuebid for D), I bid 5S to show SA and grand slam interest. Over partner's 5H, I also bid 5S to show grand slam interest.