diff --git a/.claude/skills/wizwar-duel/SKILL.md b/.claude/skills/wizwar-duel/SKILL.md
index ad99ef8..de6dd57 100644
--- a/.claude/skills/wizwar-duel/SKILL.md
+++ b/.claude/skills/wizwar-duel/SKILL.md
@@ -198,6 +198,17 @@ probing legality is free, so when unsure, try it and read the error.
   warps rewire, routes invert. After any rotate/relocate event, throw
   away every cached route and re-run the router.
 
+## The board is a torus (from Eric, after game eleven)
+
+- The warping rims mean there is NO center and NO edge: take the right
+  column and sew it onto the left — identical geography. "Central" and
+  "peripheral" seats are rendering artifacts of where the map unrolls.
+  Thinking in those terms is a trap that limits your options (his
+  words). Judge NOTHING by coordinates: distance is graph distance,
+  threat is graph threat, and the router (BFS over edges + warps) is
+  the only geometry that exists. Mentally re-unroll the map from
+  wherever you stand — every wizard is the center of their own map.
+
 ## The board is the truth (I keep paying for this one)
 
 - NEVER narrate a persistent effect without re-verifying it in the