The four main styles of Chinese calligraphy, commonly referring to 正 zhèng, 草 cǎo, 隶 lì, and 篆 zhuàn

The four styles identified by Wei Heng of the Jin Dynasty, specifically 草 cǎo, 章草 zhāng​cǎo, 隶 lì, and 散隶 sàn​lì

The four styles recorded in the Song Dynasty work Xiaoxue Ganzhu, namely 古文 gǔ​wén, 篆 zhuàn, 隶 lì, and 草 cǎo