ik si (li shi, the history) of the system, beyond the early legends, dates back to Red Junk opera performers and anti-Qing rebels Wong Wah-Bo and Painted Face Kam, and passed down from constables Fok Bo-Chuen and Fung Siu-Ching to their disciple Yuen Kay-San of Foshan, who taught it to the modern day grandmaster, Dr. Sum Nung of Guangzhou (who had previously learned from Cheung Bo).