diff --git a/docs/re/BACKLOG.md b/docs/re/BACKLOG.md
index 74135f91..326c9385 100644
--- a/docs/re/BACKLOG.md
+++ b/docs/re/BACKLOG.md
@@ -204,6 +204,20 @@ unknown, what evidence exists, and what the first step would be. Move an item in
   corpus insists on proving. 🟡 Still unread: `sub_8226DC80` (kind 1) entirely, and
   slot 60 past the `t < 0` rejection.
 
+* ✅ **(2026-08-27) THE TRIGGER MECHANISM IS READ END TO END — the kind-1 condition
+  is the SAME test with a pre-filter. [structures/isl-trigger-node](structures/isl-trigger-node.md).**
+  `sub_8226DC80` is `sub_8226DAF8`'s twin: diffing instruction by instruction, 33 of
+  the first 86 differ and **every difference before index 65 is a register rename or a
+  branch target**. Both resolve the route name (`sub_8217FA08` → `sub_823012D8`),
+  index `[phase+324]` by `payload+0`, require `rec+100 != 0`, and copy the two 3-double
+  vectors out of the unit record. Then kind 0 calls vtable slot 60 directly, while
+  **kind 1 first computes an INLINE point-to-point distance** (three `fsub` against the
+  route point, `fmul` + two `fmadd`, `fsqrt`) and **returns 0 if it exceeds `f31`, the
+  same radius** — before calling **the same slot 60**. So both kinds run the identical
+  point-to-segment test; kind 1 only adds a cheap early-out and does not spawn.
+  ▶️ Trigger work remaining is peripheral: which unit-record fields A and B are, slot
+  60 past the `t < 0` rejection, `payload+8`, and the kind-1 path in the drain.
+
 ## ✅✅ SOLVED — the mission freeze was a modal sign-in dialog (2026-08-26)
 
 `XamShowSigninUI` opens a modal dialog and `xeXamDispatchDialog` blocks the
diff --git a/docs/re/structures/isl-trigger-node.md b/docs/re/structures/isl-trigger-node.md
index f0bd5f4c..88b9975d 100644
--- a/docs/re/structures/isl-trigger-node.md
+++ b/docs/re/structures/isl-trigger-node.md
@@ -248,13 +248,47 @@ two positions; a previous/current pair would make this the standard
 frame-rate-robust waypoint test, and that is exactly the kind of tidy reading
 this corpus makes itself prove. Not proven here.
 
+## ✅ The kind-1 condition is the SAME test with a cheap pre-filter
+
+`sub_8226DC80` turns out to be `sub_8226DAF8`'s twin. Diffing them instruction
+by instruction: of the first 86, 33 differ — and every difference before index 65
+is a register rename or a branch target. Both do exactly the same thing up to
+that point:
+
+* resolve the route name (`sub_8217FA08` → `sub_823012D8`), leaving the route
+  point in `[r31+112/120/128]`;
+* index `[phase+324]` by `payload+0`, require `rec+100 != 0`;
+* copy the two 3-double vectors out of the unit record.
+
+Then they part:
+
+| | kind 0 — `sub_8226DAF8` | kind 1 — `sub_8226DC80` |
+|---|---|---|
+| next | calls vtable slot 60 straight away | **inline distance first** |
+| | | `fsub` ×3 against the route point, `fmul` + 2 `fmadd`, `fsqrt` |
+| | | `fcmpu` vs `f31`; **if > the radius, return 0** |
+| then | — | **calls the same vtable slot 60** |
+
+```
+8226DDC4  fsqrt f0, f0
+8226DDC8  fcmpu cr6, f0, f31      ; f31 = the node's double, the radius
+8226DDCC  bc    4, gt, return-0   ; too far -> reject without the segment test
+8226DDD0  lwz   r11, 0(r30)
+8226DDE8  lwz   r11, 60(r11)      ; the SAME slot 60
+8226DDF0  bcctrl
+```
+
+**So both trigger kinds run the identical point-to-segment test.** Kind 1 adds a
+point-to-point early-out against the same radius and, per the drain, does not
+spawn. The trigger mechanism is now read end to end.
+
 ## 🟡 Not settled
 
 * ~~What the drain actually spawns.~~ ✅ Resolved above: built-in 19's nodes carry
   a real routine offset at `+28`.
 * ~~Whether `+24` selects between the two node kinds~~ ✅ It does — see above.
-* ~~What the kind-0 condition tests~~ ✅ Read above. **`sub_8226DC80` (kind 1) is
-  still unread entirely.**
+* ~~What the kind-0 condition tests~~ ✅ Read. ~~`sub_8226DC80` (kind 1)~~ ✅ Read —
+  the same test with an inline distance pre-filter.
 * **Which unit-record fields A and B are** — `rec+64/72/80` vs `rec+32/40/48`.
 * **The rest of slot 60** past the `t < 0` rejection (a second constant at
   `0x820B0000+25192` is loaded next).