Strawman: Puzzle X3

STR-X3 Puzzle

Your opponent leads the Cdiamonds. You must follow suit, and you want this trick. One of your piles shows the Jdiamonds, which does not beat the Cdiamonds. Your hand holds the Kdiamonds (which beats it) and the 2diamonds (which does not).

Which do you play?

Reveal answer

Answer

The Kdiamonds, from your hand. The Kdiamonds wins the trick and the Jdiamonds on your pile loses it, so the two cards do not cost you the same. The tip to play the pile card applies only when two cards cost you the same. You want this trick, so you play the Kdiamonds.