You may have elected to defend, working out that East could win the first club trick, switch to diamonds for two winners there, and then West could shift to hearts to ensure a heart trick for the defense. That’s pretty good analysis ... but not quite good enough.
What about the case when declarer ducks the Ê9 at trick 1? Now if East overtakes his partner’s spot to get the two diamond tricks, dummy’s club holding is good enough for two heart discards: dummy rises with the ace when West shifts to hearts; then declarer uses dummy’s high trumps for a ruffing finesse against East’s last high club. And if East lets his partner’s nine-spot win the first trick, he gets the heart shift, but declarer simply wins the heart ace and sets up one diamond discard with a double ruffing finesse.
Ducking at trick one ensures that declarer loses only 1 club and two diamonds ... or 1 club, one heart and one diamond. So put your money on the declaring side of this hand.
Oh, yes ... the card that tells the tale of this hand? Naturally, it’s dummy’s Ê5: the little fellow was quite proud of his role at trick1, since playing him would accomplish something that playing any of the three honor cards could not do: making 4Í!