Earth occupies a distinct structural position within the five phase system that the other four elements, arranged around it, do not share: where wood, fire, metal and water form a cycle each generating the next in sequence, earth traditionally sits at the center of the arrangement, the phase the other four pass through or rest upon rather than simply one more link in the chain. The Earth Face Shape, tu xing lian, described as broad, thick and squared, with a wide jaw and full, heavy features across a face roughly as wide as it is long, reflects that centrality in visual terms, a shape read as solid and settled rather than pointed or elongated the way the wood or fire shapes are.
Practitioners read this shape as belonging to someone steady, reliable and patient, qualities that match earth's own traditional association with solidity and support across the wider five phase framework, in medicine where the earth phase governs digestion and nourishment, and in astrology where it governs stability and endurance. The Earth Face Shape's own reading in mian xiang is therefore not an isolated physiognomic judgment about jaw width, it is one more application of a single, much older account of what earth as an element is held to mean wherever the five phase system appears.