Tricks AB, 1
YZ, 0
1. A↷ Y B Z
8♣ 3♣ A♣ 5♣

Trick 2.

Tricks AB, 2
YZ, 0
2. A Y B↷ Z
Kg♣ 4♣ Knv♣ 2♠

Trick 3.

Tricks AB, 2
YZ, 1
3. A↷ Y B Z
2♣ Qn♣ 3♦ 3♠

Remark.—By the first discard Z shows his strong suit to be spades. In an ordinary hand, Z might afterwards throw a diamond. But here, Y must be strong in diamonds, in order to save the game; and it is important for Z to keep the power of leading that suit more than once.

Trick 4.