The valley spirit is one of the book's strangest images, and one of its most important. A valley is the lowest point in a landscape — water collects there, life gathers there, things grow there. Lao Tzu is saying the source of everything has that quality. Not a mountain peak, not a throne, not a bright shining presence, but a low receptive hollow that things naturally flow into. Christ landed at the same place when he taught that the meek inherit the earth (Matt 5:5). Both are pointing at a kind of fertility that only the low place has. The mountain is impressive but nothing grows on it.谷神 (gǔ shén) — valley spirit. Foundational TTC image; recurs implicitly in ch. 28 ("spacious vale"), ch. 32, ch. 39, ch. 66. Matt 5:5 parallel: standard in comparative meekness/humility readings (Thomas Merton, John Wu).