AbstractWe derive the fine-structure constant from the rendering algebra R12 ∼= M12(C) with zero free parameters. Four principal results are established. (1) The 12-gon Area Identity: the regular 12-gon inscribed in the unit circle has area exactly Nc = 3 (since sin(π/6) = 1 2), so the geometric defect is δ = π−Nc—a direct bridge between continuous geometry (π) and the discrete colour Casimir (Nc); among all regular polygons, only the 12-gon has area equal to an integer that also equals Nc. (2) Generalised Landauer Allocation: extending the flux-tube allocation of Paper XLVII to continuous geometric cost, the defect leakage is 1/δ = 1/(π − Nc), with the normalisation c = 1 fixed by the same principle that determines ζ(Nc). (3) Dimensional Allocation Theorem: the NLO self-referential correction Kknot = Z(N+1)/N3 is derived by classifying the selfreferential series Z/Nk by physical sector: k=0 (LO, already included), k=1 (M3 sector, excluded from the trunk at 30σ), k=2,3 (baryon surface and volume), k≥4 (truncated by D=3). (4) KMS Observation Normalisation: the factor 1/Tw follows from the same mechanism as |Vus| = exp(−Nc/Tw). The complete formula