This conundrum was written by Eddie Kantar and was originally published in the book Kantar for the Defense - Volume 2 - you can find out all about it further down the page.
We are East.
Opening Lead: ♣3
Dummy plays low and you win with the king, declarer playing the ♣5.
What do you play at trick two? Why?
It must be safe to return a club. If declarer has the ♥A you cannot defeat the hand, and if declarer has the ♣Q he cannot use it without first giving up the lead. You're covered.
You return the ♣4, declarer plays the ♣10 and partner the ♣J. How do you read the club suit?
Declarer has the ♣Q . If partner had the ♣Q J he would have played low (or the ♣Q if he could have afforded it). Playing a high honor unnecessarily denies a higher remaining honor. Therefore, the play of the ♣J denies the ♣Q .
At trick three declarer leads a low diamond from dummy. Which diamond do you play? Why?
The ♦A. Declarer is leading up to his ♦K for his eighth trick.
You win the ♦A, partner plays the ♦2. What do you play now? Why?
The ♥3. There is no future in either minor so you must go for four heart tricks. Your low heart play promises either the ace or king. With a lower honor you would have led the honor to prevent declarer from ducking the lead into partner's hand. Even though partner did lead from a weak club suit instead of a stronger heart suit you have come to the rescue…again. You take four heart tricks to defeat the contract one trick.
1- When a defender plays a high honor unnecessarily he is either unblocking or denying a higher honor.
2- A defender holding 10xx, Jxx or Qxx, needing three or four quick tricks from the suit should lead the honor when dummy to the right has small cards; leading low guarantees the Ace or King.
Kantar invites his reader to direct every play towards the goal of beating the contract in a variety of hands, bringing focus on counting tricks, points and distribution. Problems range from an intermediate to semi-advanced level and knowledge of basic card combinations is assumed. Each book concludes with a complete list of themes for its 100 problems.