This conundrum was written by Eddie Kantar and was originally published in the book Kantar for the Defense - Volume 1 - you can find out all about it further down the page.
We are East.
Opening Lead: ♥Q
Declarer wins in dummy, draws three rounds of trumps ending in dummy, partner discarding two hearts, and ruffs a heart in the closed hand.
Declarer continues by cashing the ♣K, ♣J, and leading a low club to dummy's ♣Q. On the ♣A declarer discards a low spade. Partner discards three hearts on the clubs.
At trick ten a low spade is led from dummy.
1.What was declarer's original distribution?
The count in every suit is clear. Declarer started with 4-1- 5-3 distribution. He has stripped the hand and the defense needs three spade tricks to defeat the contract.
2.Which spade do you play, why?
From your point of view the only spade holding in partner's hand that will defeat the contract is the A J 10. If partner has that holding, you must play the ♠Q to prevent declarer from ducking the trick into your partner.
Key Lesson Pointers
1. Count every hand as if your life depended upon it. Get in the habit. It gets easier after a while. (Like in about 10 years)
2. Know how many tricks you need at any given moment to defeat the contract.
3. When a hand has been totally stripped, and declarer gets around to the last suit, you should know declarer's distribution and how many tricks you need from this suit.
4. In a strip and end play situation, second hand frequently must play high to prevent partner from getting endplayed.
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.