BerylliuMM, on 2024-December-20, 02:00, said:
Thank you for the clarification! If I'm understanding it correctly, after this double, N would know S is holding something more than only soft points like ♥Q, ♦Q and ♠J, and it's very likely S would have at least an A on the unbid suits, then this hand can very likely hit slam?
It is difficult to assign any individual card to any particular hand on this auction. NS are cramped by the preempt, and have to make decisions under pressure. This involves a lot of educated guessing. As South I would not double, but instead I would force to slam. I feel like South is better off cutting the knot than risking passing the decision back to North. It may well backfire though, on auctions like this you are always only playing the odds.
BerylliuMM, on 2024-December-20, 02:00, said:
Another thing I'm curious about is the possibility of a grand slam. (Let's say it's IMP and/or NS is far behind) As far as I know 5N before agreeing on the trump suit is forcing to small slam only. Would N bid something like 6♣ to show void (idk if that's the exact meaning for this bid)? Then with N's strength of 3-level takeout and 11 good points in hand, S would give it a try?
You were careful to give the state of the match, but I still want to show the numerical context of bidding grand slams at IMP scoring. Let's say the opponents are likely in a small slam, and we rate to take 12 or 13 tricks exactly. Bidding the grand rather than the small slam, at IMP scoring, when vulnerable (as we are here) gains +750 points or +13 IMPs. Conversely, if there are only 12 tricks, bidding the grand scores -1530 points or -17 IMPs. Based on these rewards we would need to be approximately 57% sure of that 13th trick before bidding the grand is percentage.
However, there's a complication. The opponents might not be in slam. This happens to me on the regular - not to put too fine a point on it, but people aren't exactly great at bidding slams, or at competitive bidding, let alone at combining them. Let's go through the numbers assuming the opponents are in game. Now the small slam gains +750, or 13 IMPs, regardless of the number of tricks. The grand gains +1500 (+17 IMPs) if there are 13 tricks, and scores -780 (-13 IMPs) if there are only 12. Suddenly we're risking 26 IMPs to gain 4 by bidding the grand, which requires a confidence of approximately 87%.
The actual odds depend on how likely you think it is that the opponents find the slam. My experience is that they usually do not, so I want very high confidence that we're taking 13 tricks before I bid a grand. And you just can't get that kind of certainty on a pressure auction. So in line with that I have a soft rule to never bid a grand slam in competition - there just isn't enough room to share the information required to make it a good proposition. It's not absolute of course, the game is too rich and complex for that, but keep in mind the odds are typically not in your favour.
Now if, despite all that, you still want to look for grand slam you can use the bidding or bypassing of 6
♣ to show or deny a first round club control. It is common to play 5NT as pick-a-slam here, and you could make (and I have made) additional agreements about the difference between 5NT and 6
♣, both of which commit us to slam on this auction. This requires good partnership agreements though, do not spring this on partner without prior discussion (and committing the agreement to paper, because it likely will take a while before it comes up again and you may need a memory refresher in between).