What is a jeep method in ancient China?

It is an ancient string notation in China's traditional notation, and Si Er notation has been used for a long time in Chaozhou music. Since the Ming and Qing Dynasties, orthography, Western Qin, Kunqu Opera, Waijiang and other operas have been introduced into Chaozhou, and Gongchi music has also been introduced. Therefore, two partials "b" and "Fan" are often inserted in the trio and sextet of the spectrum.