# 490d Mirror checkpoint after C474

25 September 2026 UTC. **C474 complete; C475 unexecuted.** 5 steps remain in the current authorization. Current decisions override archived next-step text.

## Current result

The +500-translated split word and the inherited C429 Noah-held word E_3706² have the same full affine map, slope625/529 and effective pivot3706. The translated word needs absent pivots4120/3256 and absent upper intermediate3670; the inherited held word2648/3706→2556/3706→2456/3706 is fully sourced. Its input is the inherited C287 i3 17K corner.

## Earlier results in this batch

**C470**: All 51 sourced 1150-year coordinate pairs (101 label pairs) produce 408 fixed-pivot E trials: 16 have integer outputs and three have both outputs sourced. The admitted pairs are1955/3105→1805/3055 at3680,2020/3170→1956/3206 at2756, and2148/3298→2020/3270 at3620. Only the middle case has a complete sourced2K predecessor,2148/3206 at3620.

**C471**: All three1250 outputs have a matched-context MT Shem-death versus SP-primary/LXX-OFF Shem-birth binding, giving600+650. Their endpoint changes are−150/−50,−64/+36 and−128/−28. The first two-K ancestry fails at missing2093/3151; the third fails integrality at every fixed first pivot; only the established middle case has a sourced predecessor.

**C472**: The complete1250 inventory contains74 coordinate pairs and130 label pairs. Three disjoint matched-context families contribute24 coordinate pairs each: MT Shem-death/SP-primary-or-LXX Shem-birth; MT Flood-start/SP-primary-or-LXX Noah-birth; and MT Flood-close/SP-companion Noah-birth. Two extra MT Noah-death/SP-companion Shem-birth pairs complete the coordinate inventory; eight additional label pairs are aliases of core coordinates. All three admitted E outputs lie in the Shem family.

**C473**: All24 matched1250 contexts form typed triplets: Shem-family A maps to Flood-start/Noah-primary family C by+500; SP C maps to Flood-close/Noah-companion family B by−1, so B=A+499. There are48 typed+500 maps and24 qualified−1 maps. None of the six translated admitted E comparisons has its full input/anchor source support.

## Baseline and standing scope

C469 is the authenticated baseline. Its checkpoint is frozen in sources/C469_CHECKPOINT.md. The fixed local reflection centers are 3188, 3190, 3248 and 3250, each an existing MT Noah birth record. The 528 labelled Noah/Shem/Flood records occupy 373 integer BC coordinates. These local source comparisons do not replace the January-AD1 global Mirror. C469 establishes the complete shared-word interval ladder 2148/3206→2020/3170→1956/3206, spanning 1058→1150→1250 at pivots 3620 then 2756. Its source certificate has seven distinct coordinates. C465’s mixed-cycle 12→12 label count covers vertices only; including its operator anchors gives 48→12, as clarified in C469. The SKL appendix and corrected LXX8464 observations remain supplemental; no redirection follows. C432’s E excerpt locator was corrected in C434 and carried through C469 to File_46 L3, lines117–133; prior arithmetic already used25/23.

Mirror/529 focus: K=529, E=25/23, P=70/69; J=300/299 remains File02 gap conversion, not a calendar date operator or Residue Protocol. Regular Gears are Noah/Shem/Flood only. SP person companions are local to Noah/Shem; Flood close is an independent event boundary. Both500/100 and502/98 bindings remain valid; SP primary Noah death retains its inclusive/harmonic qualification. LXX native Cainan is ON; OFF is theoretical removal. Global paired Mirror January AD1; local junction January AD2; no civil year zero. No new source point, phase, fitted axis, upstream/cumulative Gear, primer reopening or canonical/graph edit. Capture now; canonize later. Coordinates, source labels, context aliases and derived comparisons remain distinct. Counts are not independent historical witnesses.

## Limits and verification

C429 and C287 are inherited results. This step does not rediscover their ladders or expand the operator menu. Coordinate aliases, native/theoretical Cainan status, and annual phase ancestry remain separate.

8 calculation checks and 25 source/predecessor authentication checks passed. Main result files replay byte for byte. These are root-agent checks, not an independent-agent review or independent historical witnesses.

## Best next bounded step

C475: Compare all four authenticated C429 Noah-held ladders with their Shem-minus500 partners, the derived split-pivot factorizations, and the translated split words. Resolve every anchor and intermediate against the frozen register and keep the active eight-pivot menu separate.

The3706 case joins the current split word to an inherited17K corner. Comparing the finite set of four previously recorded held ladders can distinguish a general affine identity from the specific source/context conditions that admit the split word.

Continue within the authorized batch and reassess after the next result.