4♦ 7♣
K♣ J♣
x-------------x
| Y |
| |
| A B |
| |
| Z |
x-------------x
10♦ 8♦
5♥ 3♣
Hearts are trumps. Z holds the two commanding diamonds and the
thirteenth trump. Clubs have not been led. Z leads ♣ 3 in the hope
that A may hold the ace and not play it.