The story of the Bar Kokhba revolt in the 2nd century CE culminates in the rabbi Judah ben Baba initiates 5 new rabbis and sends them away before being killed himself. (The Talmud, Arsène Darmesteter, 1897.)

This story bears some similarity to the 5 disciples of Shaolin who fled the burning temple and went on to found the Hung Society (as in Hung Gar / Hung Kuen) in order to restore a Han Chinese to the throne. (JSM Ward & WG Sterling, The Hung Society Vol I, 1925)

Both sets of 5 disciples have the goal of reestablishing some kind of legitimate authority, though via very different means. If the number 5 is not literal, it might come from the shamanistic observation of the 5 visible planets for horoscopes and divination purposes.

This is in keeping with my hypothesis that most ritual aesthetics, especially those with special attention to numbers, have their roots in shamanism, and Chinese martial arts is no different.