The following tale alternatively known as ""Meeting Zhou Tong By Chance"" and ""Swordplay under the Moon"" belongs to the ""Wang School Shuihu"" of Yangzhou storytelling. It acts as a spin-off story (), which means it takes place in the same setting as "Water Margin", but is independent of the main story line. The tale takes place after Wu Song kills the man-eating tiger, resists the charms of his sister-in-law and accepts a mission from the magistrate to transport money to Kaifeng, but before he becomes a bandit. It explains how he came to learn swordplay from Zhou Tong: