diff --git a/schemas/fssbodysignals-README.md b/schemas/fssbodysignals-README.md
index 1d8108e..051a825 100644
--- a/schemas/fssbodysignals-README.md
+++ b/schemas/fssbodysignals-README.md
@@ -24,6 +24,10 @@ The primary data source for this schema is the ED Journal event
 Please read [horizons and odyssey flags](../docs/Developers.md#horizons-and-odyssey-flags)
 in the Developers' documentation.
 
+#### SystemName
+You MUST add a `SystemName` string containing the name of the system from the 
+last `FSDJump`, `CarrierJump`, or `Location` event.
+
 #### StarPos
 You MUST add a `StarPos` array containing the system co-ordinates from the 
 last `FSDJump`, `CarrierJump`, or `Location` event.