# C27 — Civil-year counting agrees with the Mirror coordinates

22 September 2026 · Step 5 of the authorized 30-step Mirror continuation (C23–C52).

For a left endpoint −b and right endpoint +a, the paired endpoints are (b+1)t/b n BC and AD a t/(a+1)n. Both same-season civil counts give b+a:

`(b+1)+a−1 = b+(a+1)−1 = b+a`.

| Branch | Family | BC pair | AD pair | Elapsed |
| --- | --- | --- | --- | --- |
| N01 | 13 | 4421t/4420n BC | AD 2457t/2458n | 6877 |
| N01 | 17 | 5289t/5288n BC | AD 3705t/3706n | 8993 |
| N01 | 20 | 5293t/5292n BC | AD 5288t/5289n | 10580 |
| N02 | 13 | 4420t/4419n BC | AD 2458t/2459n | 6877 |
| N02 | 17 | 5288t/5287n BC | AD 3706t/3707n | 8993 |
| N02 | 20 | 5294t/5293n BC | AD 5287t/5288n | 10580 |
| N03 | 13 | 4419t/4418n BC | AD 2459t/2460n | 6877 |
| N03 | 17 | 5287t/5286n BC | AD 3707t/3708n | 8993 |
| N03 | 20 | 5295t/5294n BC | AD 5286t/5287n | 10580 |
| N04 | 13 | 4418t/4417n BC | AD 2460t/2461n | 6877 |
| N04 | 17 | 5286t/5285n BC | AD 3708t/3709n | 8993 |
| N04 | 20 | 5296t/5295n BC | AD 5285t/5286n | 10580 |

Thus N02's Creation-to-reflected-Flood interval is 4420t/4419n BC to AD 2458t/2459n: 4420+2458−1=6877 and 4419+2459−1=6877. Subtracting one from the two signed-coordinate magnitudes instead would give 6876 and mix the conventions.

Zero in this geometry denotes the paired axis, not a civil year-zero date. Reflections invert the seasonal pair; they do not preserve both suffix numerals. The checks use only the already registered cross-axis paths and do not infer new event dates from a numeric centre.

**Validation.** 13 exact arithmetic/structural checks passed. The ten frozen dependencies passed hash verification; all three generated outputs replayed byte for byte in isolation, and the original dependencies remained unchanged. This step reads completed certificates and does not execute their campaigns.

**Scope and provenance.** Controlling File_18 and File_09 remain unchanged. Regular Gears apply only to Noah/Shem/Flood; SP person companions only to Noah/Shem. Creation and Conquest fields remain fixed. Native LXX ON, explicitly derived OFF, independent Flood start/close, and paired suffix inversion at January AD 1 remain in force. No civil year zero, upstream Gear transport, primers, Rounded campaign, or localized −33 is introduced. These are new continuation reports, not recovered historical Reports 11–25. Evidence is conditional on the supplied project model, not a proof of literary intention or independent historical dating.

**Source locators.** File_09 §3.1 (paired Mirror); File_18 §§2.1.3, 3.1–3.2, 6B and 6D (qualified regular and cumulative fields); frozen C15 typed graph, C16 domain certificate, and C22 reduced scale/constraint certificates.

**Best next bounded step — High sufficient.** Locate the 13-fold interval inside the 17-fold interval, retaining the unequal flanks.