TRICK 1.--With the ace and a small card, to your partner’s high
card lead at “no-trumps,” the ace should usually be played, but B
cannot afford to overtake his partner’s king, as it would eventually
establish the ten of spades for Y.
TRICK 3.--Unless A holds the king of hearts, the game is lost,
no matter what B may lead. To make a possible re-entry for A, B
sacrifices his queen of hearts. Z hopes that B has but two hearts and
so refuses to win this trick.
It makes but little difference what Y now leads. A’s spades must make.