[apollo1201]

IMPs. Partner deals and opens 1D (3 only if 4432), in a strong NT context. You’re vul, and your nv RHO jams the auction with a 4S bid.

You have a promising hand but unclear direction.

A
xx
ATxx
Qxxxxx

Is an (undiscussed) 4NT natural to play (630 better then 500) or for minors (offensive hand with a sort of fit for opener and longer in the other minor)?

What if vuln were reversed?

What if the opening is 1H (BW or minors)?

I (probably too quickly) ruled out X in case partner would bid H with a shapely hand, although in that case they wouldn’t bid 5H directly but 4NT followed by 5D over my 5C to convey the H message and we’d not find ourselves at an uneasy level.

In all cases, partner duly answered her HA to my identified as such 4-aces BW (no fit established) 🤣🤣. At least it was an answer I could easily pass, and this made after sg C lead to A, C ruffed, establishing the suit, and no DQ guess to make after that.

A nice ending but unsatisfactory intellectually speaking. Any advice is therefore warmly welcome.

[DavidKok]

I play 4NT as 'two places to play' on this auction. Partner will usually bid their better minor, and if that's the one suit I don't have I correct to the cheapest alternative.

In my opinion this is the best allocation of the bid by far based on frequency. You usually won't have a strong hand with a solid spade stop if they jump to 4♠. It's the same reason why double here is more 'optional' than 'penalty'.

I'd play this the same way if partner opened 1♥, or 1NT, or didn't open at all.
As an aside, I think Blackwood/keycard asking methods are massively overrated. In general I think people are too willing to give up otherwise useful bidding space to get some keycard asking bids in, and competitive auctions are the worst offender. The highest priority should be to get to the right strain on the 5-level, and you need all the tools you can get to have a reasonable shot of finding it. Even if you somehow would be able to find the right strain, it is almost never clear whether your combined hands have a trick-taking potential of 11, 12 or 13 tricks (or if you're sacrificing). These issues take priority over finding keycards, so use your limited bidding space to show them. As an example, if partner opened 1♥ I play 4NT then pulling to 5♥ as a constructive raise, inviting to 6, while a direct 5♥ is just competitive. I think this message is more important than the number of keycards partner might hold.

[mikeh]

I pretty much agree with David

We have a rule. If we open 1M and they bid 4m, 4N is keycard.if we open 1Suit and they bid 4M, 4N is two places to play, but if we then bid 5H over partner’s 5m (regardless of what partner opened, but only if the opp bid 4S) then the delayed 5H is stronger than 5H over 4S. This is slightly different from David’s approach, which seems to apply only after partner opens 1H.

[DavidKok]

mikeh, on 2022-January-20, 09:54, said:

If we open 1M and they bid 4m, 4N is keycard.if we open 1Suit and they bid 4M, 4N is two places to play, but if we then bid 5H over partner’s 5m (regardless of what partner opened, but only if the opp bid 4S) then the delayed 5H is stronger than 5H over 4S. This is slightly different from David’s approach, which seems to apply only after partner opens 1H.

This can create a problem if you have a club-heart two-suiter, especially if partner opened 1NT or a short club. Partner might not be allowed to show a preference for diamonds if you cannot correct to hearts.
However, if partner has already shown hearts, any heart raise takes priority over diamonds. Arguably 4NT then pulling 5♣ to 5♦ should also show some constructive heart raise (what else?), but this is not something we've ever discussed.