R-266: the coin is the first disabling blow, and it lands in round two

Reading both ends of the four-player cut — seed 5's sweep and seed 2's wipe —
says the fight is not decided by round five but by whoever lands the first
disabling hit, on average in round two. Both sides disable on one good blow, so
each one thins the return fire and makes the next likelier; nothing pulls a
fight back toward the middle.

tools/first-blood.mjs measures it: 49.7/50.3 on who strikes first, and 23.1% vs
66.5% wipes on either side of that. Six against six is the control at 8.6% vs
22.4%. A reading tool, not a guard — it records nothing, and no figure from it
goes on a generated page.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/REVIEW_LOG.md

@@ -5809,3 +5809,48 @@ fights that get there. 68% of fights reach round five with none of them down.
 **The lesson is the one this log keeps recording, one layer out.** A number that cannot be
 reproduced is a claim, whoever holds it. It was caught because another session tried the
 citation rather than trusting it, which is exactly what a citation is for.
+
+## R-266 — the coin is the first disabling blow, and it lands in round two
+
+R-265 left a finding standing: the four-player cut of CLEAN GROUND is bimodal — 23.1% of
+fights end with nobody down, 45.0% with everybody down, and only 11% near the published
+mean. It said the fight is *decided by round five*. That was true and it was the wrong
+frame: round five is where the outcome is already legible, not where it is decided.
+
+**Reading one fight from each end says why.** Seed 5 is the clean sweep. Neil puts 5 into
+a leg on the first exchange; 5 of 10 is exactly the major-wound threshold, so one of the
+three is disabled before anybody else has landed anything. A is down in round 2, C in
+round 3 on a critical, B in round 4 before it acts. **The party is hit once in the whole
+fight** — 4 points through Neil's armour. Seed 2 is the wipe, and its first two rounds
+produce a single 3-point scratch; the column lands three blows in round 3, Kate goes 12 to
+0 and Arun is disabled by a critical, and the cut is two effective attackers against three.
+
+**Both sides disable on one good hit.** The major-wound threshold is half of max HP and it
+is the same rule in both directions — the neighbours have 10, the agents 11 to 13 — so an
+average blow takes a fighter out of the fight. Every disable removes an attacker, which
+thins the return fire, which makes the next disable likelier. Nothing pulls a fight back
+toward the middle once it has tipped, which is the whole of the bimodality.
+
+**Measured, `tools/first-blood.mjs`, 2000 runs at seed 11:**
+
+| first fighter out | share of fights | mean round | wipes among those |
+|---|---|---|---|
+| the party strikes first | 49.7% | 1.7 | **23.1%** |
+| the column strikes first | 50.3% | 1.7 | **66.5%** |
+
+A true coin, settled in round two, worth **43 points of wipe rate**. Six against six of the
+column is the control: first blood still matters there and matters far less — 8.6% against
+22.4%, a 14-point swing, at mean round 1.3. One fighter is a sixth of that line and a
+quarter of the cut, so the same blow compounds less. This is a property of the cut, which
+is what the histogram said by a different route.
+
+**Dominic should be read before anyone is handed him.** In both narrations he attacks at
+`vs 1` — four attempts in the seed 5 fight, all of them hopeless. The four-player cut is
+three effective attackers, not four, and a table that assigns Ashcroft to a player without
+saying so has quietly made the coin worse.
+
+**`tools/first-blood.mjs` is a reading tool, not a guard.** It records nothing and no
+figure from it belongs on a generated page — the bestiary and the scenarios read guarded
+artifacts only. It is in the repo rather than in a scratch directory for one reason: the
+number above was quoted to another session, and R-265's lesson is that a number the
+person quoted it cannot re-run is a claim, not a result.