His bidding convention most in vogue today is Exclusion Blackwood, or Lackwood or Voidwood. Once a suit has been agreed, directly or by implication, a jump in a new suit shows a void and asks partner how many aces are held outside the suit bid. Many players nowadays graft on the Roman Key Card Blackwood responses.
On this hand from the 1999 Generali European Bridge Championships, Seven Hearts was reached by the Danish Ladies team in just seven bids.
East opened One Diamond, West responded One Heart, East bid Two Spades and West rebid Three Hearts. Now East jumped to Five Clubs, agreeing hearts by inference and showing a club void. West's reply of Five No Trumps showed two aces - the king of trumps being treated as an ace - plus the queen of hearts. Her "aces" had to be 4A and !K - if she had held 2A she would have disregarded it.
Knowing the trump suit to be solid, East jumped to the heart grand slam. On a club lead East ruffed low, then catered for a possible 5-2 diamond break by ruffing a diamond, cashing two trumps in hand, ruffing another diamond, drawing trumps, then returning to dummy with a spade to cash the four diamonds.