# 490d Mirror checkpoint after C306

24 September 2026. Latest completed: **C306 — Admitted selector alternatives and exact phases.**

C306 audited eightGear1 selector combinations and32exact component comparisons. Fourcenter600 alternatives exist, eachwith exactly one±1 interface residual. Jointzero/zero pairs599/601 have component widths598.5,599,599.5 or600.5,601,601.5, never600. Whole-pair ancestry is retained; alternative bindings are diagnostics, not adopted changes.

## Standing context

C276: the selected cross-index alignment fixes δ=h−f=598; source transport alone does not. Absolute placement remains a separate premise. Preserve source and map roles, annual indices and ±1/4 phase ancestry. Co-located images do not identify events.

K=529; E=25/23; P=70/69. Global Mirror January AD 1; established local junction x=1, January AD 2; no civil year zero. Regular Gears Noah/Shem/Flood only. No cumulative/upstream Gears, primer reopening, canonical/graph changes or new global axis/z-law. Capture now, canonize later.

Supplement: LXX Creation 5494 BC +8464→AD 2970 versus reflected Conquest AD 1406 gives1564→1700 by25/23; Jared4534→AD3930 versus reflected Exodus1446 gives2484→2700. LXX Creation→Jared960, MT460; offsets1380/880; difference920→1000. AD3746/2300 superseded. Awareness only.

C-series reports remain distinct from original unprefixed Reports01–10 and unestablished interrupted Reports11–25. The superseded AD1905–1911 lookup remains unexecuted.

## Verification

19 mathematical/domain checks and 8 source authentication checks passed; two generated readouts replay byte identically. Author review only. File_18, File_09, C265 certificate and C127 unchanged; graph208 nodes/382 duration edges.

## Best next bounded step

C307: Derive a typed affine normal form for the joint source relations, separating dependent equalities, context conversions and phase actions.

Reason for selecting it after C306: The available local choices are exhausted; a reduced model can now explain the compatibility boundary without accumulating duplicate numerical witnesses.

High is sufficient unless a later dependency requires reassessment. The next step was not executed as part of C306. The authorized batch continues through C310.