Why did Siu Yeun San and his family (i.e. his wife and infant son) cross the Ah-Mun Pass into the territory of the Sung Kingdom on that fateful day? Siu obviously didn't go into Sung territory looking for a fight (although that's precisely what he got). The Sius didn't strike me as being tourists (the Northern Sung Dynasty and the Khitan Liao Empire were enemies at the time), nor did it appear that Siu was a tradesman traveling into Sung on business.