Very simply you can open 4NT which asks partner if they hold an ace.
| Response | Meaning |
| 5♣ | No aces |
| 5♦ | The ace of Diamonds |
| 5♥ | The ace of Hearts |
| 5♠ | The ace of spades |
| 5NT | 2 aces |
| 6♣ | The ace of clubs |
| 6♦ | Three aces!? |
Alternatively you can play a step response:-
| Response | Meaning |
| 5♣ | No aces |
| 5♦ | The ace of Clubs |
| 5♥ | The ace of Diamonds |
| 5♠ | The ace of Hearts |
| 5NT | The ace of spades |
| 6♣ | Two aces |
| 6♦ | Three Aces!? |
Again the most important thing is make sure you agree what you are playing with partner…as the specific ace convention doesn’t arise very often I would suggest you play the first alternative described here.
Please make sure you can handle any response…if you hold:-
Now the opposition are bound to lead a red suit and take you one off in 6♠.
Whereas if you have this you can cater for any response:-