[PhilG007]

An opening bid of 4NT is a rare bird. In most bidding systems,it calls on partner to cue bid any Aces he holds
by bidding its suit. However,I have noticed,particularly in BBO tournaments that 4NT has been opened and on
asking for an explanation got the reply "Blackwood for Aces" To me this is perplexing. I was always under the
impression that Blackwood operated once a trump suit had been agreed,either directly or by inference.
To do so without any suit being mentioned at all is,to me just bizarre. Am I missing something here(?)

[nige1]

PhilG007, on 2019-November-16, 07:51, said:

An opening bid of 4NT is a rare bird. In most bidding systems,it calls on partner to cue bid any Aces he holds
by bidding its suit. However,I have noticed,particularly in BBO tournaments that 4NT has been opened and on
asking for an explanation got the reply "Blackwood for Aces" To me this is perplexing. I was always under the
impression that Blackwood operated once a trump suit had been agreed,either directly or by inference.
To do so without any suit being mentioned at all is,to me just bizarre. Am I missing something here(?)

IMO, the Acol opening 4N ask is flawed (If you must find about specific aces, it's probably better to deny than show them). Hence almost any other meaning is an improvement. e.g. a slam try in a minor, both minors, a balanced power-house, or ordinary Blackwood.

[gordontd]

nige1, on 2019-November-16, 08:05, said:

IMO, the Acol opening 4N ask is flawed (If you must find about specific aces, it's probably better to deny than show them). Hence almost any other meaning is an improvement. e.g. a slam try in a minor, both minors, a balanced power-house, or ordinary Blackwood.

Good to point out that it's an Acol bid and is not part of "most bidding systems" as claimed by the original poster.

[pescetom]

nige1, on 2019-November-16, 08:05, said:

IMO, the Acol opening 4N ask is flawed (If you must find about specific aces, it's probably better to deny than show them). Hence almost any other meaning is an improvement. e.g. a slam try in a minor, both minors, a balanced power-house, or ordinary Blackwood.

My variant of the Acol 4N ask can show 2 aces and not just a specific ace, also has developments to explore specific kings when possible for that matter. I'm dubious about slam try in a minor or a balanced power-house (can show both clearly after 2♣), but both minors with moderate slam interest is worthy of thought (and such a strong preempt) I agree.

[kreivi68]

If you play Namyats convention or similar, you can add one-suited major blockbusters to it. I wrote an article about the idea to The Bridge World (July 2016) called SuperNamyats.
So 4C/D opening would be either strong preempt or very strong one-suiter with heart/spade suit. After responder signs off in 4H/S opener continues with strong variant:
4NT is key-card ask, new suit is Exclusion Blackwood and jump to 6C/D shows strong two-suiter missing only one honor in either suit. This leaves 4NT opening for more
useful purposes.