Try today’s offering as a declarer play problem.
As South, having followed the fastest route possible to four spades facing a constructive raise, you receive the diamond six lead to the queen and king. This feels like a promising start: Only a 4-1 diamond split will present any problems, and West would not have led the six from 10-9-7-6, so turn your mind to finding a way to make when East has four diamonds.
One possibility is to find the heart ace onside. You must draw trumps first, of course, to avoid a potential diamond ruff, and you are pleased to find them 2-2. Next, you lead a heart to the king. To your chagrin, East takes that with the ace, but he returns the suit for you to ruff. You are not reduced to finding diamonds 3-2 just yet; what else could you try first?
Lead a club, ducking in dummy — West would have led the ace or king if he held both. East wins with the jack and continues with the club king, but as the cards lie that is the end of the road for the defense. East does not have another club to play, so he must either give you a ruff-and-discard with a heart lead, or open diamonds with the seven — which you would you cover with the eight — or open up diamonds. If he leads the seven, you cover with the eight. If he selects a high diamond, you can run the lead to dummy and then finesse the eight on the way back.
Note that this line of play would also work if East had three clubs to the ace and king. Of course, if diamonds had originally broken 3-2, they will still break at the end of the deal.