If Declarer is Smart, Defenders must be Smarter by Marty Bergen (USA)

Players often blame the opponents' excellent declarer play for their lack of success.  Sometimes, your opponents only play as well as you let them.  If it appears that declarer is playing too well, you may not be putting up the best defense. Take this hand's defensive problem as an example.

Contract: 4S
Lead: D4 (3rd from even, low from odd)

                          S Q96
                          H AJT75
                          D KT
                          C 743
                                    S 83
                                    H KQ93
                                    D AQ73
                                    C JT9

             West     North     East     South
             Pass      2H       Pass      3S
             Pass      4S     All Pass

     Trick 1. D4 DK DA D2
     Trick 2. DQ D6 D5 D10
     Trick 3.  ???

What do you (East) lead at trick three? Answer before reading on.

Did you make the obvious shift to the CJ? Here is the entire hand:

Lead: D 4
                          S Q96
                          H AJT75
                          D KT
                          C 743
                S 2                 S 83
                H 642               H KQ93
                D J9854             D AQ73
                C K862              C JT9
                          S AKJT754
                          H 8
                          D 62
                          C AQ5

Declarer was in no hurry to finesse; instead, he had spotted an attractive alternative. If East held the King of clubs, declarer could later win a trick with his CQ. After winning the Ace of Clubs, South set out to establish dummy's heart  suit.
Declarer led the H8 to Dummy's Ace, ruffed the H5 with the S10, S7 to dummy's S9, H7 ruffed with the SK, S4 to dummy's
queen, H10 ruffed with the SA, S5 to dummy's S6 and at trick 11, cashed the Jack of Hearts for the tenth trick.
Should declarer have been allowed to play this well?
After winning the first two diamond tricks, most players would lead a club, but what is the hurry? If declarer had loser(s) in clubs, his only hope to avoid them would be to develop hearts.
With three stoppers, East knew that declarer could not utilize dummy's heart strength. East should have made sure that South could not take advantage of the heart length by returning a "trump" at trick three. With only two trump entries remaining in the dummy, South is now one entry short of establishing the hearts.
Marty Bergen is a ten-time North American National Champion and is recognized as one of the world's most innovative bidding theorists.