diff --git a/mrbgems/mruby-string-ext/mrblib/string.rb b/mrbgems/mruby-string-ext/mrblib/string.rb
index 48604e873..aa788303e 100644
--- a/mrbgems/mruby-string-ext/mrblib/string.rb
+++ b/mrbgems/mruby-string-ext/mrblib/string.rb
@@ -1,29 +1,5 @@
 class String
 
-  def partition(sep)
-    raise TypeError, "type mismatch: #{sep.class} given" unless sep.is_a? String
-    n = index(sep)
-    unless n.nil?
-      m = n + sep.size
-      [ slice(0, n), sep, slice(m, size - m) ]
-    else
-      [ self[0..-1], "", "" ]
-    end
-  end
-
-  def rpartition(sep)
-    raise TypeError, "type mismatch: #{sep.class} given" unless sep.is_a? String
-    n = rindex(sep)
-    unless n.nil?
-      m = n + sep.size
-      [ slice(0, n), sep, slice(m, size - m) ]
-    else
-      [ "", "", self ]
-    end
-  end
-
-
-
   ##
   #  call-seq:
   #     str.insert(index, other_str)   -> str