Buddha-nature turns the path inside out: instead of a long accumulation toward something absent, practice becomes the removal of what obscures something already present. The consequences are enormous and East Asian Buddhism is built on them — Zen's insistence on sudden seeing, Dogen's claim that practice is not a means to awakening but its expression, the whole idiom of polishing a mirror rather than building one. Theravada declines it, holding that it smuggles back exactly the permanent essence the anatta teaching removed, and the argument between the two positions is one of the oldest live disputes in the religion.