Zen Buddhism has been practiced in East Asia for well over a millennium. During this lengthy historical period, the Zen tradition incorporated into itself many of the spheres of culture – or cultural practices – that were dominant in its time. Theoretical thinking, or philosophy, was one of these, and the Huang Po texts are fine examples of its Zen form in the early Sung period. Nevertheless, Zen Buddhism is not primarily a philosophical movement. Indeed, criticism of theoretical reflection from the perspective of Zen meditation practice is ever present in Zen literature. Even when Zen Buddhists do philosophize, as Huang Po certainly did, practice, not theory, is the emphatic focus of reflection.