There's an Expert Behind the Wall

Pei Zhao had worked as a menial laborer at the outer estate for three years. By day, he hauled goods, delivered firewood, and cleared ditches. At night, he ran errands for the city gangs, all to earn a few extra copper coins. Then, while being punished one day, he discovered a wall beneath an old tower. Someone had left a sentence on it: “All seventy-two ultimate techniques can be countered.” Pei Zhao had assumed the person who wrote those words was long dead. So he casually left a sentence of his own on the wall: “How do I sink my qi?” The next day, a few more words had appeared on the wall. “Who told you to hold your breath?” “Idiot.” Pei Zhao stood before the wall for a long time. Someone was on the other side. Only many years later did he learn that the ordinary-looking wall had never been separating just two people.