M J Bridge
Theory and Conventions
Partner opened 4NT
Partner’s bid is the specific ace ask.
The standard responses are:-
Bid 5♣ with no aces;
bid 5NT with two aces;
bid the named ace with one ace.
J 9 7 6
A J T 5
J 8 6 4
Partner opened 4NT.
Not a very prepossessing collection, but partner has asked you to name your ace, and so that is what you do.
Intermediate and above
There is much to be said for agreeing to reverse the 5NT and 6♣ responses.
By responding 5NT with just the ace of clubs partner might, once in a lifetime, be able to stop in 5NT.
Opener’s first bid
Context - Responder’s first bid.