The author explains the exceptional ability shown by musicians to keep in memory the traditional musical repertoire, at the same time when they appear as the best interpreters of traditionalised music. For S. Trebinjac this “ambivalence”—which is neither said, nor recognised, and which remains uneasy to discern—is a Chinese specificity, and probably absent from the Soviet world. However, isn’t it surprising to meet musicians who, when they listen to early twentieth-century recordings, are capable to sing the same songs, and to identify their interpreters? It is this memory that is described here as the “private side” of musical learning, since it belongs to the secret world of any musician in Xinjiang. At the same time, these same musicians participate in the traditionalisation of their own music, when they contribute to its making (which means censorship and self-censorship) and diffusion. When they play pieces of the traditional repertoire—ritual forms of musical expression—for advocating the policy of birth limitation, for denouncing the disadvantages of polygamy, or in a more remote past for praising Mao’s greatness, or even for denouncing the vileness of the Western great powers, musicians offer the “public side” of their knowledge. Numerous testimonies illustrate both sides of musical learning in twentieth-century Xinjiang, and more generally in China.