[Stephen Tu]

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Given its choice not to overcall 2nt at this vul, (fine, whatever), shouldn't it take advantage of this and pass the takeout double for 1100? Pretty clear at these colors with the excess strength IMO.

And if not going to pass, should it not bid 3nt to simplify the auction? I don't think 15 is too strong for 3nt, despite the possibility as here of missing a slam. I don't have to have the CJ. Why the nebulous 3♠, which should be very low priority?

Also, I don't think South's 4 level bids are very well defined after the cue bid. Probably I am supposed to bid 4d in theory opposite a better defined cue bid, not 4h. But *all* of South's bids I believe show a "rebiddable" suit, e.g. 5+ cds? I think after a cue it should just be a 4 cd suit, although hearts is arguably 5 here.

[pigpenz]

agree with everything you said
if not going to sit for double the cue bid just adds confusion
maybe 4NT if its invitational to 6 not ace asking would be better but
that is looking at both hands

if it was BW master solvers
pass 10
3NT 9
3♠ then 4NT 8
3♠ then passing 1

[barmar]

It doesn't overcall 2NT because GIB plays this shows 16-18, and it's a point short.

The rule for converting the takeout double requires a rebiddable suit, and its suit is only biddable.

It has a rule to bid 3♠ with 13+ total points, and another rule to bid 3NT with 12-15 HCP and spades stopped. The 3♠ rule has higher priority for some reason, probably to do with fitting it in among all the constructive suit bids. I agree this seems wrong, since it makes it impossible to reach 3NT.

[Stephen Tu]

It has "rules" for converting takeout doubles to penalty? Shouldn't it simulate instead? 2 bullets should make up the difference between "biddable" and "rebiddable".

Having rebiddable spades to pass is a good rule when contemplating converting when weaker, but sim should be able to handle both cases?

[barmar]

It's not possible to "simulate instead". As I've explained a number of times, simulation works by finding rules that match hands similar to the one it has, and then running simulations of what would happen if it made the bids specified by those rules. So in order to include converting the takeout double to penalty in the simulation, there has to be a rule that produces this action, and it has to match a hand similar to the one it has.

However, bidding rules can also have flags related to simulations. A rule can specify "Never override with simulations" or "Always simulate before selecting this rule". In this case, the rule for converting has the "always simulate" flag (so that it doesn't convert just because it has a good suit, the hand has to be suitable in ways that are hard to express explicitly in the rule), but the rule for cue bidding has the "never override" flag.

One of these days I'd like to implement Colchamiro's rule of 9 for converting takeout doubles: # cards in opponent's suit + # honors in opponent's suit + level of contract >= 9. Currently, there's no way for bidding rules to get the number of honors in a suit, so this would require a change to the program to make the information available.

[Stephen Tu]

I don't see why it can't be changed to simulate instead on this hand. Supposedly, you said that the rule for converting a takeout double required a rebiddable suit in the opp's suit. So one could change the rule to only require a biddable suit, but "always simulate", and remove the "never override" producing the cue bid. Then wouldn't it match the rule and think about it? Don't see why one would have "never override" on any selection in a bidding situation over a preempt.

Never override should be more for things like opening bids, responses to opening bids, generally constructive auctions which for first few bids should be by the book. In competitive auctions one needs judgment.

[barmar]

I suspect the "never simulate" flag is on the cue bid rule is there to prevent it from being overridden by some other rules, not specifically the conversion rule. Unfortunately, we can't get more specific than this; we can't say "Use a simulation to choose between cue bid and passing, but don't allow the simulation to choose 4♥."

BTW, that hand doesn't fit Mel's rule.

If GIB held your hand, you would get to the desired 3NT contract. It wants a twice rebiddable suit to bid on the 4 level, so it's end-played into bidding 3NT even if it doesn't have a stopper.

[Stephen Tu]

My position is that the "never simulate" flag on the cue bid is clearly a mistake and should be removed. Cue bid in response to takeout double should be fairly low on the priority list, particularly over 2s, not highest. On hands worth a gf, I would expect 4h with 5+ hearts, 3nt with a spade stopper in preference to cue bid. It can cue with GF without spade stopper, maybe with 4 only hearts, and maybe with 17+ slammish values. And with biddable spades always simulate pass vs. all the other options.

So what if it doesn't fit Mel's rule? Mel's rule I'm 100% sure is intended for borderline situations with weak hands, not hands such as this + A + AQ on the side, with an assumed 27+ hcp on your side! Are you seriously suggesting that one should blindly follow Mel's "rule" regardless of overall strength & relative vulnerability? Mel's rule is applied when you have KJxx of trumps and out , or maybe say KJxx of trumps and one side ace. Not 2 side aces, extra Q+J, no long suits, 27+ HCP and unfavorable vul!

And getting endplayed into 3nt because partner denies a stopper and all my bids show twice rebiddable suit isn't my idea of good system construction. Takeout double already strongly suggests no rebiddable suits, when your bid is forced by partner 4 level suit bids can't be defined as twice rebiddable. This has to be fixed.