diff --git a/src/sgfParser/property.py b/src/sgfParser/property.py
--- a/src/sgfParser/property.py
+++ b/src/sgfParser/property.py
@@ -85,7 +85,7 @@ def compose(vTypeA,vTypeB):
 	def f(s,start):
 		i,a=vTypeA(s,start)
 		if i>=len(s) or s[i]!=":":
-			raise ParserError("a composed property value separated by ':' expected",s,i)
+			raise ParserError("expected a composed property value separated by ':'",s,i)
 		i,b=vTypeB(s,i+1)
 		return (i,Composed(a,b))
 	return f