♥ J 2
♦ Q J 8 6 2
♣ A K J
| WEST | NORTH | EAST | SOUTH |
| 1♠ | |||
| pass | 2♦ | pass | 2♠ |
| pass | 3♠ | pass | 4♣ |
| pass | 4♠ | all pass |
South opens 1♠.
North responds 2♦, a 2/1 force to game.
South has a big hand, perhaps in the slam range, but first priority is to set a trump suit. So she contents herself with a rebid of 2♠. North agrees on trumps by bidding 3♠ (not Fast Arrival).
South now makes her slam try by using a Control-showing cue-bid. She bids 4♣, showing first round control of the suit (Ace or Void).
North's next bid would be a control-showing bid of her own - IF SHE HAD ONE. Since she cannot win the first round of either red suit she just returns to 4♠.
South realizes that they are off two red Aces and passes.
Notice that South did not fall into the Blackwood trap. If she HAD asked for Aces, North would have shown one Ace and South wouldn't know what to do next. She might have figured the odds favored that one Ace being a red one and tried the slam. Moral: Don't use Blackwood when you have a void.
Deal 21
♥ K Q 7
♦ K 7 3
♣ --