Declarer mumbles "Thank-you, partner" and pauses to make a plan. Whilst declarer is ruminating let’s see. South presumably has about 11 points for his 2NT bid, leaving East with about 7 points. So we can forget about the chance of East winning a trick with the
A and cashing lots of Hearts because East is highly unlikely to have the two red Aces. Anyway, declarer wins with dummy’s
K (East following with the 4) and leads a Diamond to the
K in hand. Declarer eyes your 10 with interest and follows with the
9. Now, early in the play you have to make a crucial discard. What is it? And, more to the point, why?