In today's era of bidding gadgetry, no convention is more gimmick-loaded than what started as a simple method of locating a major suit fit—the artificial two-club response to an opening bid of one no trump.
The majority of today's players consider this convention a contract bridge innovation and credit its invention to Sam Stayman. However, back in the dark ages of auction bridge when nobody bid four-card majors and even longer minor suits were suppressed in favor of the no-trump bid that offered the short road to game, some thoughtful players noted that many no-trump contracts were defeated when game in a four-card major would have been sure. So, with good hands, they would take out the no-trump bid to two clubs to ask whether the no-trump opener held four cards in either major.
Stayman, with his then partner George Rapee, rescued this convention from desuetude and restyled it for contract bridge—with good effect on hands like this.
At this point in the proceedings there is some question what South should do. North's two-club inquiry need not necessarily guarantee that he holds four cards in either major; he may only have been seeking reassurance about a weak suit in his own hand. Should South show his second major?
If he does so, North, who underbid considerably when he bid only three no trump, will leap to six hearts. He can do this with certainty that the combined hands will include at least 33 points; even if South has a minimum no trump, his showing of two four-card suits promises a doubleton worth the one point that will bring the combined hands into the slam zone.
The gadget bid that eliminates the problem of whether the no-trumper should show his second major is an immediate response showing both majors and also announcing whether the opening bid was a minimum or maximum. (Be it known that your reporter has not adopted this practice, leaning as he notoriously does to natural methods.) After a two-club response from North, South rebids three clubs to show both majors and a minimum, three diamonds to show both majors and better than a minimum opener. In this case, he would bid three diamonds and North could leap to the slam at hearts.
If they do not succeed in uncovering the four-four fit in hearts, it is not unthinkable that North-South should wind up in a contract of six no trump. They enjoy the required 33 high-card points—but no luck. The club finesse is off and the spades do not split; with careful defense, South is held to 11 tricks.
Played at six hearts, however, South's distributional value provides the winning margin. Against the opening lead of the diamond jack, declarer wins with his ace. He cashes the heart king and leads to dummy's heart jack. The bad split demands temporary abandonment of the trump suit, and dummy's club queen is led for a finesse. Though this loses to West's king, it is not fatal.
West's diamond continuation forces dummy's king. Declarer cashes his club ace and goes to dummy's queen of spades to shed his last diamond on the club jack. Then South ruffs dummy's last diamond and cashes his queen of hearts. He returns to dummy with the spade king and throws his losing spade on dummy's ace of hearts, which draws East's last trump. The ace of spades in declarer's hand captures the slam-fulfilling trick.
If you don't mind acquiring another complexity for you and your partner to remember, there is no reason why you should not adopt the gadget that lets the no-trump bidder show both majors at once. However, a simpler way of locating a major suit fit is always to confine the two-club response to hands which include at least one four-card major.