TRICK 1.--Z false cards the king of spades in order to
deceive his adversaries.
TRICK 2.--The lead of the club suit must come from Y, but if
a low heart is led, it will take out Y’s only card of entry. With the
purpose of making two cards of entry, Z leads the high cards from his
own hand.
TRICK 4.--As all the hearts have fallen, Z can safely
overtake the jack, to lead the queen of clubs toward the ace. Should
Z continue with another round of hearts, Y would have no way of
obtaining the lead after the club suit was established. The low heart
must be saved as a card of entry.