diff --git a/docs/re/BACKLOG.md b/docs/re/BACKLOG.md
index 469f5034..c0253eba 100644
--- a/docs/re/BACKLOG.md
+++ b/docs/re/BACKLOG.md
@@ -354,7 +354,11 @@ search cannot find a *schedule*.
   and section 2's exactly 96, in 11/11). **Section 0 is a point list**
   (13 467/13 467 inside the bbox) and **section 2 is a plane list** — unit normal,
   signed distance, and a point, with `n·p + d = 0` to float round-off in
-  **133 573/133 573**. Section 1 (96 B) still ❔.
+  **133 573/133 573**. Section 1 (96 B) still ❔ in meaning, though its slot
+  regions are censused. ❌ **The static coupling search is exhausted**: every
+  index-shaped field in the cell payload has been followed into all three
+  sections and checked for spatial agreement against controls — nothing above
+  chance. Settling it needs the PE code that reads `REGN`, not more correlation.
   See [`structures/regn-map-grid.md`](structures/regn-map-grid.md).
 * 🔴 **`hidden/DefTables.pak` is NOT it** (checked 2026-08-24). The three
   unnamed schemas are more **model/render** tables in the same vocabulary as the
diff --git a/docs/re/structures/regn-map-grid.md b/docs/re/structures/regn-map-grid.md
index 6002a3c7..94821e96 100644
--- a/docs/re/structures/regn-map-grid.md
+++ b/docs/re/structures/regn-map-grid.md
@@ -337,4 +337,40 @@ section-1 indices, and holding cell-local coordinates.
 ✅ Incidental, from the same sweep: `u32` slots at **+0, +8 and +12** of the
 payload record are below `0x10000` in **100 %** of records, while +4, +16, +20
 and +24 are in only 11 % and +28 never — so the record has three index-shaped
-fields and four wide ones, whatever they refer to.
\ No newline at end of file
+fields and four wide ones, whatever they refer to.
+
+## ❌ …nor the point list, nor the plane list — the static coupling search is exhausted
+
+**2026-08-26.** The previous test only tried section-1 targets, which left the
+obvious gap: the payload's three index-shaped `u32`s might address the **points**
+or the **planes** instead. Tested the same way — follow the index, ask whether
+the target lies inside the cell that referenced it:
+
+    RANDOM control                    0.203 %
+    +0  -> points 0.17 %   planes 0.16 %
+    +8  -> points 0.81 %   planes 0.09 %
+    +12 -> points 0.81 %   planes 0.09 %
+
+All at the control rate. The two 0.81 % cells are 4× the baseline, and I am
+**not** treating that as a signal: across this and the previous iteration I have
+now run on the order of twenty of these tests (three index fields × three
+sections × two readings × several offsets), and at that count a single 4×
+enrichment on ~8 000 trials is what noise looks like. Reporting it as a lead
+would be exactly the multiple-comparisons error that a long hypothesis sweep
+invites.
+
+### Where this leaves `REGN`
+
+✅ Decoded: the header and grid, section 0 (points), section 2 (planes), section
+3 (the cell index), and the strides and field regions of section 1.
+
+❌ Not decoded, and **not reachable by the tests available statically**: any link
+between the grid and the geometry. Every index-shaped field has been followed
+into every section and checked for spatial agreement, against controls, and
+nothing rises above chance.
+
+❔ **What would actually settle it** is the code — find what reads a `REGN`
+object in the executable and watch which fields it dereferences. That is static
+PE work (`/work/*.pe`, offset = VA − 0x82000000) of the same kind that cracked
+the `.slb` packing phase, and it is the honest next step rather than a
+twenty-first correlation.
\ No newline at end of file