This conundrum was written by Patrick O'Connor and was originally published in the book, Demystifying Defense - you can find out all about it further down the page.
We are East. Our hand is:
Demystifying Defense
South opens 1♥, we pass and North bids 2NT, the Jacoby convention, showing four-card support for opener’s hearts and at least an opening hand. Partner passes and South jumps to 4♥ showing a minimum 1♥ opening. All pass, we lead the ♥J, a safe lead from three adjacent honors, and dummy comes down.
Lead: ♥J
Demystifying Defense
South draws trumps in three rounds, ending in hand. Partner shows out on the first round and discards the ♣3, then the ♠2, then the ♣4.
What do partner’s discards tell us?
A high discard in a suit would show interest in that suit, so it seems that partner is not at all interested in clubs or spades.
Declarer leads the ♣K.
What do we play now?
Partner has discouraged spades and clubs so we have to hope that he has diamonds. So we take the ♣A and switch to the ♦7. We lead our highest spot card to indicate that we have nothing helpful in the suit. Fortunately, partner has the ♦AKJ and takes three diamond tricks to defeat the contract. Here is the full deal:
Post Mortem
It is vital to take notice of partner’s discards. Partner could only give an encouraging discard in diamonds by giving up a trick, so the only alternative was to give discouraging discards in the other suits.
O’Connor addresses the hardest aspect of cardplay: defense. After carefully explaining the basic concepts, he takes the reader through forty problems, using an ‘over the shoulder’ style, and explaining every play as it is made. Beginners typically have more trouble with defense than any other part of the game, and this book will go a long way towards removing their unease.