Song Huizong, this guy, is an emperor who likes writing and painting. He took a fancy to his writing, and his position soared, ruining the Northern Song Dynasty. At that time, he was one of the four great calligraphers in the Song Dynasty. Later generations gave his position to his younger brother Cai Xiang because of his bad reputation. Song Sijia was Su Shi, Huang Tingjian, Mi Fei and Cai Jing, and Cai Jing was later replaced by Cai Xiang.