LIGHTNER DOUBLE. A lead-directing double of a slam contract. If competent opponents bid a slam voluntarily, it may be expected that they will fulfill their contract or fail by one trick. Thus a normal penalty double is unlikely to gain much. In 1929, Theodore Lightner devised a more useful interpretation of this bid. A double by the hand not on lead is conventional. Partner is requested to choose an unusual lead that may result in the defeat of the slam. A conventional double of this sort excludes the lead of a trump, a suit bid by the defenders and probably any unbid suit. The player who doubles expects to ruff the lead of a side suit mentioned by the opponents, or else to win two top tricks in that suit. Some experts treat this double quite rigidly. They define the double to mean that partner must lead dummy’s first-bid side suit. Other good players, including Lightner, interpret the bid more loosely. An unusual lead is requested and partner must deduce from the context which suit is required.
♠ A J 9 8
♥ A K J 7 4
♦ Q 7
♣ 9 7
♠ 10 7 ♠ 4 3 2
♥ 10 8 6 5 3 ♥ —
♦ J 10 9 8 ♦ A K 5 4 3 2
♣ 10 8 ♣ 5 4 3 2
♠ K Q 6 5
♥ Q 9 2
♦ 6
♣ A K Q J 6
South plays 6♠ after opening 1♣ and getting a response of 1♥. East doubles for an unusual lead. West leads a heart,East ruffs and cashes the ♦A for the setting trick. Without the double, West would have led a diamond, which declarer would have covered from dummy. East would be forced to win the only trick the defense could take. Related: Lead-Directing Doubles, Double For Sacrifice and Mini-Lightner.
SOURCE: "Conventions", The Official ACBL Encyclopedia of Bridge, 7th ed. Horn Lake: American Contract Bridge League, Inc., 2011, page 296. Print