Coupling Geometry Case Study XXIV: The Aztec Triple Alliance, 1428–1521

This case study applies Coupling Geometry to the Aztec Triple Alliance, and its role in the portfolio is foundational in the literal sense: the framework’s theoretical papers cite Marvin Harris’s analysis of the Aztec state — protein scarcity in the hemisphere’s most animal-poor environment expressing itself through tribute extraction of human bodies and a state-constructed cosmology that legitimated the extraction as cosmic necessity — as the exemplar of the causal order the axioms assert, and until the April 2026 investigation no formal scoring existed behind the citations. The study presents that scoring, corrected twice. The mature imperial system of 1470–1519 is coded, in the proposed set offered here for adoption, at C = 6.3 (I1 = 6.0, I2 = 7.0, I3 = 6.5, I4 = 7.0, I5 = 5.0): a hegemonic tribute empire of some five hundred altepetl under indirect rule, its extraction intensity at the top of the pre-modern comparative band, its information environment deliberately engineered into near-monopoly — the burning of the conquered peoples’ codices under Tlacaelel and their replacement with the Fifth Sun history is the portfolio’s clearest case of refractive-field construction as policy — and its subsystem structure genuinely modular, with the Triple Alliance capitals institutionally distinct and the tributary periphery retaining local dynasties. The correction history is stated in full, because two of the five indicators required direction repair: the programme’s v3 rescoring audit corrected the original I5 (altepetl autonomy is low interdependence, 6.5 → 5.0), and the present conversion identifies the same error class in I4, scored in the superseded pluralism direction (4.0) and converted here to the uniformity convention (7.0) — the third catch of the programme’s 2026 indicator-direction audit. The pre-registered record is restated accordingly: seven of nine predictions confirmed, both failures direction artefacts, with the comparative-position prediction failing under the recorded correction alone and restored if the proposed I4 conversion is adopted. Beyond the corrected formalisation — whose confirmatory circularity with the framework’s prior commitments is disclosed rather than disguised — the study contributes a reclassification: the Spanish conquest is read through the portfolio’s exogenous-intervention taxonomy as a Mode IV termination of a non-cascading system, executed by calibration-range bypass (steel, cavalry, epidemic disease) and, distinctively, by coalition capture of the empire’s own modular periphery — Tlaxcala and the defecting tributaries as the demonstration that the low interdependence which made the hegemonic empire cheap to run made it cheap to take. Adversarial examination, by Mesoamericanists above all, is invited. Case Study XXIII: The European Union, 1951–Present – Case Study XXV: Tokugawa Japan, 1603–1868