If they don t cover, they don t have it . . .
By Patrick Jourdain (Great Britain)

The favorite declarer ploy of Lars Blakset of Denmark, which relies on the element of unawareness in the defender's mind, was threatened by the publication of Zia’s BOLS Tip: If they don't cover your honor with the missing honor, they don't have it.
Nevertheless the trick remains effective, provided you promise not to tell anyone that Lars employs it.

                   S KT7532
                   H T
                   D AKT9
                   C T4     
      S QJ9                   S 6
      H AKQJ84                H 962
      D 62                    D Q43
      C 87                    C AK9632
                   S A84
                   H 753
                   D J875
                   C QJ5

     West      North      East     South
               Blakset             Auken
                          Pass     Pass
     1H        2S (a)     3C (b)   3S (c)
     Pass      Pass       4H       Pass
     Pass      4S         Dbl      All pass

(a) A three level preempt in any suit except the one opened!
(b) Implying heart support to the three level
(c) South is prepared for 3S OR 4D

When Jens Auken bid 3S Blakset realized his partner must have a reasonable holding in diamonds. Heused the knowledge of the double fit to take the profitable sacrifice. Four spades doubled was a popular contract. Some declarers went only one down
because East began with ace, king and another club. West was forced to ruff with a trump trick, while declarer ditched his losing heart. Declarer later lost a diamond. Jan Jansma, sitting East, told me of a great play by his partner Jan van Cleeff, who deliberately gave false count with the West cards in an effort to divert East from continuing the suit. "Unfortunately, I knew from the club pips that partner had two, " said Jan, modestly adding "and unwisely assumed he had made a mistake with the signal, instead of working out what was going on. I continued a club, thinking to kill the club trick, instead of switching to a heart." The East at Blakset's table made no such mistake, leading a heart at trick one. The second heart was ruffed, and Blakset drew two rounds of trumps with the king and ace. Now he led the diamond JACK from dummy. When West played low, Blakset not only went up with the king,  he backed his judgment by following smartly with the TEN! Poor East, thinking his partner might hold Ax, played low. And now Blakset was back to down one and a high matchpoint score.