Reverse-Engineering How Hydrated Biological Structure Persists After Active Maintenance Stops: Xin Zhui and the Wet Preservation Regime

Biological structure persists while retention keeps pace with or exceeds the processes that erase or transform it. This study asks how external constraint regimes can prolong structural persistence after active biological maintenance stops, using Xin Zhui of Mawangdui Tomb 1 as a wet, boundary-controlled empirical case. The analysis uses reverse constraint reconstruction, reading the surviving endpoint backward through substrate, medium, transport, boundary, and environment to recover the hierarchy of conditions compatible with persistence. Reconstructed forward, the system is described as environment → boundary → transport → medium → substrate → persistence. Boundary closure and resulting anoxia are identified as the primary suppression control; the tissue-contact medium carries local hydration, redox, pH, and ionic conditions; and deep, thermally moderated burial slows continued degradation of a transformed substrate. The durable coffin-fluid pH remains unresolved and non-load-bearing, and mercury is not required as the primary preservation controller. No active bioelectric field, living physiological state, or preserved viability is claimed. The paper distinguishes documented evidence, established physical mechanisms, reconstructed quantities, unresolved states, and prospective hypotheses throughout. The broader contribution is a transferable boundary–medium grammar for comparing structural persistence across radically different constraint regimes. Xin Zhui defines the wet, boundary-controlled coordinate of that comparative framework, while prospective implications for regeneration are explicitly treated as hypotheses for future testing rather than results of this case.