[luis]

This topic appeared in my last teaching session at the Beg/Int lounge so I'll post a quick summary here.

After a 4NT bid asking for key-cards responses are:
5c = 0 or 3
5d =1 or 4
5h = 2 without the trump Q
5s = 2 with the trump Q
5N = odd number and a useful void
6x = even number and a void in the suit bid (if suit is trumps void in a suit above trumps)

You can change the 5c/5d responses to play 1430 instead of 0314 and you can also change the way you show voids, that's a partnership agreement. (Usually 1430 is slightly better than 0314 but no big deal)

After a response showing 0/3 or 1/4 the 4NT bidder has the following options:

* Signoff in the trump suit
* Ask for the trump queen to play 6 or 7
* Bid 5NT with all the keycards and interest in grand slam

It is important to bid 5NT only when you have all the key-cards, if a key-card is missing signoff or ask for the queen but never use 5NT. Why? Because responder is allowed to bid 7 after 5N if he thinks that's right.
When responder can't count 13 tricks he can show either specific kings or the number of kings he has, you have to agree with your pd what you bid after 5NT when you can't bid 7.

Example:

AQx
KQJxxx
Axx
x

Opener
1s 2h
2s 3s
4N 5s (2 + Q)
5N 7s

Since we have solid hearts so 5 spades, 6 hearts and the minor suit aces will produce 13 tricks.

How to ask for the trump queen:

A "relay": the cheapest bid available asks for the trump queen.

Example if trumps = spades

4NT 5d (1 or 4)
5h (Q?)

Now responses are:

5 in the trump suit: I don't have the queen
5N: I have the trump queen and extra values
6 in the trump suit: I have the queen and no extras
6x: I have the queen and this nice King

Important: When you know your side has 10 or more trumps bid as if you have the queen even when you don't have it. Because the Q drops. So if you have 5 card support for a 1s opening and pd ask for aces if you have 2 bid 5s (2+Q) if you have another number and are asked for the Q say that you have it.

This is a quick summary of the basic actions after using 4NT RKCB there're many variations and advanced treatments if you want more
information. Check this actions with your pd it can be good for your partnership slam bidding.

Luis