If previous bid was in a suit - 4NT asks ‘How many Aces do you have”:
After 4 NT - if all 4 Aces are held can check for Kings with 5NT:
Never use Blackwood after partner has called no trumps for first or second bid unless you have settled on a suit. In these cases 4NT is a quantitive raise.
In this case use Gerber.
Also never use Blackwood if you do not have a stopper in a suit such as if you have a void or 1 or 2 low cards
Using a bid of a jump in clubs (4C min) to ask how many Aces are held. To answer:
5C (or higher) can then be used to ask ‘How many Kings’
Bid 4NT - asks how many key cards do you have - 4 aces and King of trumps:
QUEEN OF TRUMPS?
If the answer is 5 Hearts or 5 Spades, the queen of trump has been taken care of. But, what if the answer is 5 clubs or 5 diamonds?
The 4NT bidder can still ask about the queen of trump by bidding the next higher suit available that is not the trump suit. That is, if responder answered 5 clubs, the asker can now bid 5 diamonds to ask about the queen of trumps.
Bid 5NT - asks for kings (only do this if you have 4 aces and K & Q of trumps) count excludes King of trumps
Losers are defined as the AKQ missing in the suits in your hand. Counting all the missing honours in each suit up to the number of cards in that suit gives your total losers. A suit of three or more with no A, K or Q counts as three losers. A suit of two with no A, K or Q counts as two losers.
18 minus (openers' losers + responders' losers) equals the maximum level of a contract in an agreed suit.
The calculation assumes in the first instance that an Opener has 7 losers and the Responder has 9 losers.
i.e. 18-(7+9)=2. The maximum level is 2.
However if the Responder has 8 losers, 3 can be bid in the agreed suit.
i.e. 18-(7+8) = 3. The maximum level is 3.
If Responder has 7 losers then 4 can be bid in the agreed suit.
i.e. 18 - (7+7) = 4. The maximum level is 4.
After the response, the Opener knows the number of losers in partners hand and can add her own losers. If the total of losers is 14 or less then game in a major suit must be bid.
i.e. 18-(6+8)=4 Or 18-(9+5) = 4
If the total losers are 12 or less then Blackwood can be used to evaluate a slam.
If there is a fit in a minor suit, counting losers is less valuable because making game requires 11 tricks. If responder has a fit with opener's minor suit it is often better to explore NTs.
NB. COUNTING LOSERS ONLY APPLIES WHEN THERE IS A FIT IN AN AGREED SUIT. If you are responding and you have a balanced hand do not use it. Value your hand using HIGH CARD POINTS (HCP) instead.
HCP high card points 4321 (AKQJ).