The chariot-cannon clamp
夹车炮 (a chariot doubling the cannons) lines up long-range pieces on one file to the king: the front cannon already sits at the palace heart e8, the chariot guards it from d8, and only the rear cannon is still out on the wing. Black's advisors seal their own king's corners; his horse on h9 can reach neither the file nor the killer. One slide joins all three guns: the rear cannon fires through the front cannon, the chariot makes the front cannon untouchable, and the advisors can only watch. Close the clamp.
Solve the challenge to finish this lesson.