Why were forcing-pass bidding systems banned from international bridge play?
Card editor of the London Field W.H. Whitfeld published this bridge problem in 1885. South is declarer and has the lead with hearts as trump. With a sophisticated finesse, South can win every trick. South begins by leading the ace of diamonds, which, depending on what the opponents discard, opens a possible finesse of North's jack of diamonds. Next, South passes the lead to North with a spade that North trumps. North then leads the last heart, and South discards the 10 of clubs. With the lead of the last trump and then the ace of clubs, the defenders are presented with an insurmountable dilemma. East must hold two diamonds or South takes the last two tricks in the suit by discarding a spade. However, in order to hold on to two diamonds, East must discard the jack of spades, which in turn would force West to hold the queen of spades. Since West also needs the queen of diamonds and the jack of clubs to avoid losing a trick, a discard from any of the three suits will allow South to win all of the remaining tricks by an appropriate discard.
Forcing-pass bidding systems were banned from international bridge play toward the end of the 1980s primarily because they were designed to place opponents in unusual and difficult situations, rather than simply facilitating communication between partners.1
These systems, which gained popularity in Poland, Australia, and New Zealand, functioned by requiring an initial pass to show a strong hand (typically at least 13 high-card points), while any other bid denied that strength. This approach effectively restricted the opposing pair’s ability to utilize their own bidding system unless they were the ones to deal and open the bidding immediately. Because these methods were viewed as a tactical maneuver to disrupt the opponents' ability to compete in the auction, they were ultimately prohibited in international competition.1