[notproven]

I vote for 4 Ace Blackwood. The 1♣ bid is not a suit (since it could be short). Partner knows what he's looking for, and if he doesn't, I vote for 1eyedjack's fifth option.

In regular partnerships I play this sequence one of three ways, depending upon specific prior agreement:
a) 4 Ace Blackwood (always with a short club or strong club system);
b) quantitative (shows about a 20 count, balanced, all suits at least second round control) (how often does that happen?);
c) RKC for clubs (if opener promises 3+♣).

[PhilG007]

 Tryggolaf, on 2016-May-10, 05:03, said:

Playing in a pick-up partnership in a natural 5 card majors context, you open 1♣ showing 2+♣. Your responses are up the line and you are nearly certain you play inverted minors. Partner manages to surprise you with a 4NT-bid. Regardless of the actual hand you hold, what would you think the 4NT-bid means? In addition to that question, what is your agreement on the 4NT-bid in your regular partnership?

(pass) - 1♣ [= 2+ ♣] - (pass) - 4NT

I play RKCB but as I too play the short club I would be very wary of bidding 4NT opposite a 1♣opener unless I had great strength in the suit myself. Indeed,the final contract might not even be clubs (!)

[nige1]

 Cyberyeti, on 2016-May-10, 13:08, said:

would agree with you about 1 (Key-card) but I would expect to have agreed 4♣ or 4♦ to be that.

Reasonable although, with a pick-up partner, some would fear 4♣ might be pre-emptive and 4♦ exclusion. Anyway, I wouldn't blame a partner for hoping that I correctly interpret such a bid . Partner might even intend it as a compliment. Understandably, others, like 1eyedjack would expect a pick-up partner to avoid the risk of ambiguous efforts

[Vampyr]

 PhilG007, on 2016-May-11, 13:40, said:

I play RKCB but as I too play the short club I would be very wary of bidding 4NT opposite a 1♣opener unless I had great strength in the suit myself. Indeed,the final contract might not even be clubs (!)

This is why normal Blackwood is the popular choice, and in fact no other interpretation would cross my mind, as any others would require prior agreement. I don't care how many clubs are promised; I would do the same over any suit opening bid.

Also I would have expected that if I had bid this with a pickup partner, that is how she would have understood it. This thread has been illuminating.

[SteveMoe]

Joining the chorus for Blackwood (Aces). Of course, I have to want to play 6 if partner has one Ace (or 5 of my own suit).

If I want to know keys, I make a forcing raise first (and then bid 4♣ or 4♦ ask the keycard ask. So 4N is almost never RKB over ♣).

Quantitative for me asks partner if they have extras for their bidding. Since 1♣ can be 11 - 21 HCP, 4N certainly isn't asking partner. The range is just too big. Showing partner?? There's just no need to use up the bidding space just because I hold 20 - 21.

Specific Aces? Too small a benefit window when Ole Black is available.

[perko90]

 PhilG007, on 2016-May-10, 06:46, said:

The type of player I most dread pairing up with is the one who just loves to
see the wheels go round. In the example given,I would pass 4NT and if partner started
remonstrating,I would just simply reply "We had no agreement on this" Time and again
I have stressed that in any pick up pairing you should strive to KEEP IT SIMPLE!!!!!!
Long ago,when I was a novice I was told that if you made a bid and partner didn't understand the
meaning of it,it was YOUR fault

This.
I didn't even vote because this 4NT is so unnecessary. If it's intended as RKC, keep it simple and set the suit with a forcing 2♣ bid first.
If intended as "quantitative," how would you expect a pick-up partner to know what range? Why not start with 1♦ and hear partner's rebid?

[Vampyr]

 perko90, on 2016-May-12, 01:51, said:

This.
I didn't even vote because this 4NT is so unnecessary. If it's intended as RKC, keep it simple and set the suit with a forcing 2♣ bid first.

Precisely. This is why it is normal Blackwood.

[Phil]

There is a large subset of good players that opt to play this as RKC, and another set that would play it as 19-20 and a balanced hand with poor controls. If the player is intermediate, I would probably assume 1430, only because they don't even know what standard blackwood is / or thought it was not played when one learned 1430.

However, all of this is a deviation from the standard definition of blackwood (04,1,2,3).

However, just because you loathe your partner for making this call, don't do something like pass out of spite. You are better off assuming a certain agreement than doing something purely irrational. Spiteful actions loudly proclaim that you are more interested than being right than winning.

[steve2005]

Whats with the option RKCB without a trump King? Isnt that plain Blackwood?

[Vampyr]

 steve2005, on 2016-May-12, 14:03, said:

Whats with the option RKCB without a trump King? Isnt that plain Blackwood?

Maybe. I assumed that the difference was that 5NT would ask for specific kings, rather than number of kings.

Anyway, I don't understand the large vote for keycard in clubs, since you are "nearly certain" you are playing inverted minors and therefore there will be a way to establish that clubs are agreed.

[miamijd]

This is pretty standard, actually. If an auction goes (no opposing bidding) 1any suit - 4NT, that is regular, standard (not keycard) Blackwood.

Why is this? First, there may be hands where responder only wants to know about Aces and Kings. For example: 1C - 4NT. Responder has:

KQJT9XX AKQ Ax x

Aren't you really just interested in how many Aces partner has? If he has none, you'll sign off at 5S. If he has one, you'll bid six spades. If he has two, you'll ask for Kings and bid 7NT if he has one.

OK, but what if you want to play with opener's suit as trump and want to use RKC? Well, you don't have to bid 4NT immediately. Just make a forcing raise to set trump (e.g., inverted minor raise for C or D; Jacoby 2NT for H or S). Then you can bid keycard later on. If you tell me you don't have a forcing raise, then you need to change your system so that you do (any system that doesn't have a forcing raise available is nutty).

[neilkaz]

Assuming a BBO pickup I'd just answer to regular old Blackwood.

[PhilG007]

 neilkaz, on 2016-May-13, 13:43, said:

Assuming a BBO pickup I'd just answer to regular old Blackwood.

"Old" is right Simple Blackwood nowadays is considered to be a crude museum piece,
crashing down with one blunt question and one equally blunt answer. The modern ways
in slam investigation are RKCB and cue bids.

[Phil]

 PhilG007, on 2016-May-14, 00:17, said:

"Old" is right Simple Blackwood nowadays is considered to be a crude museum piece,
crashing down with one blunt question and one equally blunt answer. The modern ways
in slam investigation are RKCB and cue bids.

if I'm building a table, sometimes I don't want a compound mitre saw. Occasionally a handsaw is the *right* tool for the job.

[masse24]

 PhilG007, on 2016-May-14, 00:17, said:

"Old" is right Simple Blackwood nowadays is considered to be a crude museum piece,
crashing down with one blunt question and one equally blunt answer. The modern ways
in slam investigation are RKCB and cue bids.

Assuming "modern ways in slam investigation," regular old Blackwood is standard here and shows a more advanced understanding of when RKCB applies and equally as important . . . when it does not apply.

[FrancesHinden]

Playing with someone good, I'd assume it was regular blackwood for aces.
Playing with a weaker player, I'd assume it was RKCB for clubs.

[lycier]

I know Gib CC is RKCB for ♣.

[Fluffy]

RCKW for clubs unless I am 100% certain we both know we play inverteed minors, that is, we used them previous board or something like. Then I would take it as quantitative.

[PhilG007]

In days gone by you were warned not to use Blackwood when you had a void.
Now it seems you can use it...as long as certain criteria was satisfied.
I'd like to know more as the two statements seem to be conflicting.

[Vampyr]

 PhilG007, on 2016-May-18, 15:49, said:

In days gone by you were warned not to use Blackwood when you had a void.
Now it seems you can use it...as long as certain criteria was satisfied.
I'd like to know more as the two statements seem to be conflicting.

Well, you can use exclusion.