diff --git a/transformation/rewriter.py b/transformation/rewriter.py
index 100073f..9c29252 100644
--- a/transformation/rewriter.py
+++ b/transformation/rewriter.py
@@ -22,7 +22,6 @@ class TryAgainNextRound(Exception):
 
 # Rewrite is performed in-place (modifying `host_m`)
 def rewrite(state,
-    lhs_m: UUID, # LHS-pattern
     rhs_m: UUID, # RHS-pattern
     pattern_mm: UUID, # meta-model of both patterns (typically the RAMified host_mm)
     lhs_match: dict, # a match, morphism, from lhs_m to host_m (mapping pattern name -> host name), typically found by the 'match_od'-function.
diff --git a/transformation/rule.py b/transformation/rule.py
index 81436ad..7db576e 100644
--- a/transformation/rule.py
+++ b/transformation/rule.py
@@ -117,7 +117,6 @@ class RuleMatcherRewriter:
 
         try:
             rhs_match = rewrite(self.state,
-                lhs_m=lhs,
                 rhs_m=rhs,
                 pattern_mm=self.mm_ramified,
                 lhs_match=lhs_match,