[The Casual]

My partner and I often had trouble determining when 4NT is Blackwood or Roman Key card; to fix this we made an agreement that 4NT is always straight BW unless the trump suit was explicitly raised or something of the like (Splinters or Jacoby 2NT). However this makes it so that in most slam bidding auctions RKCB is only really in use after a 2 level response (by opener) to 4th suit forcing and a below game level trump raise by responder - A pretty rare occurrence. Because of this it is very rare we actually use RKCB and this often leads us into slams with at least 1 natural trump loser. I figure playing 2/1 would fix a lot of these issues but how is this handled in SAYC and what are some common partnership agreements for when BW or RKCB apply?

Thanks.

[akwoo]

The usual agreement is that 4NT is NEVER straight Blackwood. When no trump suit is agreed, the last natural bid suit is presumed trump for the purposes of RKCB.

In any case where this is a bad idea, it's probably more useful for 4N to be a quantitative invitation for a NT slam anyway.

[Vampyr]

A common agreement is to play normal Blackwood only when 4NT is bid immediately after a 1-level opening bid.

[Zelandakh]

Hello and welcome to the BBO forums. This subject is more of an intermediate one than N/B so forgive me if this is aimed falsely. As akwoo says, for the most part ordinary Blackwood is nor used any more. The exception is as an immediate response to an opening bid - many play this as Blackwood, since a hand that wants to ask for key cards can start with a forcing raise (Jacoby 2NT, inverted minor, criss-cross, etc) and then make the asking bid the next time around.

For the later auction, you first have to decide if 4NT should be natural. If natural makes sense then this tends to take priority over asking for key cards. In most cases where a natural 4NT is necessary there is also a forcing call available for a raise with slam interest. In high level auctions that is often the fourth suit at the 4 level. There are also some additional meanings for 4NT that some pairs play which com,plicates matters a little bit but it is probably best not to go into that here. Instead, start with the general rule that aside from the first response, 4NT is either natural or RKCB.

Over time you will find aituations where you would have preferred to have 4NT available for other meanings. When these crop up you can discuss with your regular partner to see if they think it is a good idea. If you both think it is good then an idea would be to start a thread about it here to see if there are any issues you have overlooked and whether the idea can be implemented from general rules rather than as a specific exception (which is easy to forget).

There is also the issue of 4NT in competitive auctions, which is often different from uncontested ones. Again, I will defer talking about that for now because it is a more advanced topic and probably not suitable for this forum outside of a specific question.

[helene_t]

If a trump suit has been agreed, it is RKCB.

If it is in response to partner's natural notrump bid it is quantitative.

If it follows after an intervention over our natural notrump bid, it is to play.

In most other contensted auctions where opps bid 4M, it is "unusual", showing two suits, generally the minors if opps bid 4♥.

So far so good. The problem arises when the last bid was a suit bid by partner but we haven't agreed a suit, for example:

1♥-1♠
2♦-4NT

If you want to keep it simple, just agree that in such auctions it is always RKCB for the last named suit.

Also, if opps interfere with something other than 4M, play it as RKCB for out last named suit.

You can make a few exceptions, such as:
- a 4NT opening (many play this as asking for specific aces)
- direct response to a suit opening (ordinary BW)
- 4NT rebid after a 2♣ opening and a 2♦ relay: 4NT is natural, 28-29 points or such
- 4NT overcall after opps open 4m: natural, often based on a solid suit in the other minor and (of course) a stopper in their suit.
- If the last bid was partner's response to Stayman, or accept of a transfer: 4NT is quantitative, if you want to ask for keycards you have to make a forcing raise (after stayman, bid 3 of the other major) or use Texas instead of a Jacoby transfer.

[The Casual]

Thank you all for the suggestions, and thanks Zelandakh. I'll be sure to discuss these with my partner.

[Lovera]

 helene_t, on 2014-June-06, 06:03, said:

If a trump suit has been agreed, it is RKCB.

If it is in response to partner's natural notrump bid it is quantitative.

If it follows after an intervention over our natural notrump bid, it is to play.

In most other contensted auctions where opps bid 4M, it is "unusual", showing two suits, generally the minors if opps bid 4♥.

So far so good. The problem arises when the last bid was a suit bid by partner but we haven't agreed a suit, for example:

1♥-1♠
2♦-4NT

If you want to keep it simple, just agree that in such auctions it is always RKCB for the last named suit.

Also, if opps interfere with something other than 4M, play it as RKCB for out last named suit.

You can make a few exceptions, such as:
- a 4NT opening (many play this as asking for specific aces)
- direct response to a suit opening (ordinary BW)
- 4NT rebid after a 2♣ opening and a 2♦ relay: 4NT is natural, 28-29 points or such
- 4NT overcall after opps open 4m: natural, often based on a solid suit in the other minor and (of course) a stopper in their suit.
- If the last bid was partner's response to Stayman, or accept of a transfer: 4NT is quantitative, if you want to ask for keycards you have to make a forcing raise (after stayman, bid 3 of the other major) or use Texas instead of a Jacoby transfer.

(If you want to keep simple ...last named suit)This a point of aptention because RKCB serves for top honors in trump suit (Ace or/and King) in this case you lost the statement expecially when you have to manage with an ambigue answer (an Ace on two disponibile suits) anything else you know about Ace or King 'cause you are interested for the other suit.

[1eyedjack]

At a risk of some repetition, for which apologies ...

You would not normally mix ordinary Blackwood with RKCB in the same system.

Most experts play a mixture of quantitative (ie non-forcing invitational) 4N with RCKB, the distinction (and definition of trump suit for RKCB purposes) being a function of the preceding auction leading to 4N. In some rare occasions 4N might be neither (ie pick a suit, or simply to play when partner's last bid was 4 minor).
Furthermore, in expert partnerships 4N is quantitative far more frequently than a beginner would usually expect.
Also use of 4N as Blackwood risks the response committing you to slam on inadequate aces where the trump suit is low ranking (in the extreme, where Clubs are trumps, one ace commits you beyond 5C). Gerber (use of 4C as the ace ask) claims to overcome that, but has other problems (more valuable uses for 4C which you would have to give up in favour Gerber). Some get over this by playing that 4 of the agreed minor (or suit above it) is the ace ask, which has the dual advantage of being affordable and allowing 4N to be a contract suggestion.

At the other extreme, many beginners play that 4N is always straight Blackwood.(or play 4C as always Gerber, leaving 4N as always quantitative).

Beginners choose 4N as "always (simple) Blackwood" because
1) By not playing RKCB, they retain the option of playing Blackwood when there is no (clear) trump suit.
2) By not playing RKCB, there is no risk of confusion over which of a choice of potential trump Kings is relevant to the response.
3) By not playing Quantitative, there is never any confusion over when 4N is quantitative v Blackwood

It is not an entirely unreasonable policy in the context of a beginner partnership. For partnerships that are prone to misunderstandings, more points are lost through misunderstandings than through choice of inferior methods (confusion over meanings of doubles being another classic area).

But this policy has some obvious weaknesses:
1) By not playing RKCB then where there is a trump fit (of less than 11 cards) you fail to acknowledge that the King of trumps is (almost) as valuable as an Ace.
2) By never playing 4N as quantitative you obviously have a problem on hands where a quantitative 4N is the most appropriate use.

But if you are reading this it is presumably because you want to shift up.

As you gain experience so you gain the ability to adopt progressively more sophisticated agreements without (hopefully) also falling into the costly trap of system disagreements at the table. It is not necessary to go the whole hog in one go. And at the end of the road, not all expert partnerships distinguish the options identically.

With a regular partner you could set up a flow chart that gives priority to potentially conflicting questions, such as:

(1) has more than 1 trump fit been expressly agreed? If so, 4NT is RKCB. You need a meta-agreement to decide which is the deemed trump suit for the purposes of the responses. You are not committed to playing in that trump suit, but you do need to agree which King counts as an Ace. Possible options are (1) the first agreed suit, (2) the last agreed suit, (3) the highest ranking agreed suit. Option 2 has some attractions, because it may have some similarities with the situation where a suit is agreed by inference (per rule 4 shown later). Option 3 has some attractions, because if you commit to playing in that suit you are less likely to get too high. There are some more complex versions of Blackwood that treat both Kings as key cards.

But failing the conditions for (1) above,
(2) has precisely one trump suit been expressly agreed? If so, then 4NT is RKCB in that suit.

Failing (1) or (2) above, ie no express trump suit agreed
(3) Is there an opportunity expressly to agree all viable suits below game in a GF auction? If so, then 4NT is quantitative where you have chosen to bypass suit agreement.

Failing (1), (2) or (3) conditions, then
(4) has partner just bid a suit naturally which might be a valid contender for trumps? If so, then 4NT is RKCB in that last mentioned suit that could not have been expressly agreed below game in a GF context.

Failing any of the above 4 conditions
(5) Quantitative

I just made these up on the fly, and it contains some flaws, but you get the picture. Helen_t came up with some other scenarios which I have not catered for, so you could expand on this. For example some sequences may "set" a trump suit without requiring agreement ("self-supporting" suit, so long that it requires no support). There may be some specifically defined sequences to cater for, such as 4N following a response to Stayman or accepted transfer. Shove them into a "rule zero" if you wish. Did you have 4th suit forcing available to you at the point of bidding 4N but chose to bypass 4th suit? That could have a bearing.