diff --git a/ChangeLog b/ChangeLog
index acf758a695..c315b4184b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sun Oct 18 22:33:25 2009  Tadayoshi Funaba  <tadf@dotrb.org>
+
+	* lib/date.rb: do not require lib/delta.rb.
+
+	* lib/date/delta.rb: follows the above change.
+
 Sun Oct 18 19:14:21 2009  Tanaka Akira  <akr@fsij.org>
 
 	* parse.y (is_special_global_name): add boundary check.
diff --git a/lib/date.rb b/lib/date.rb
index 802ce8ec14..daa51d8e0e 100644
--- a/lib/date.rb
+++ b/lib/date.rb
@@ -194,7 +194,6 @@
 #     puts secs_to_new_year()
 
 require 'date/format'
-require 'date/delta'
 
 # Class representing a date.
 #
@@ -1337,9 +1336,6 @@ class Date
   def + (n)
     case n
     when Numeric; return self.class.new!(@ajd + n, @of, @sg)
-    when Delta
-      d = n.__send__(:delta)
-      return (self >> d.imag) + d.real
     end
     raise TypeError, 'expected numeric'
   end
@@ -1356,11 +1352,8 @@ class Date
     case x
     when Numeric; return self.class.new!(@ajd - x, @of, @sg)
     when Date;    return @ajd - x.ajd
-    when Delta
-      d = x.__send__(:delta)
-      return (self << d.imag) - d.real
     end
-    raise TypeError, 'expected numeric'
+    raise TypeError, 'expected numeric or date'
   end
 
   # Compare this date with another date.
diff --git a/lib/date/delta.rb b/lib/date/delta.rb
index 283faf6ac2..eacfdefc62 100644
--- a/lib/date/delta.rb
+++ b/lib/date/delta.rb
@@ -1,5 +1,6 @@
 # delta.rb: Written by Tadayoshi Funaba 2004-2009
 
+require 'date'
 require 'date/delta/parser'
 
 class Date
@@ -398,3 +399,33 @@ class Date
   end
 
 end
+
+vsave = $VERBOSE
+$VERBOSE = false
+
+class Date
+
+  def + (n)
+    case n
+    when Numeric; return self.class.new!(@ajd + n, @of, @sg)
+    when Delta
+      d = n.__send__(:delta)
+      return (self >> d.imag) + d.real
+    end
+    raise TypeError, 'expected numeric'
+  end
+
+  def - (x)
+    case x
+    when Numeric; return self.class.new!(@ajd - x, @of, @sg)
+    when Date;    return @ajd - x.ajd
+    when Delta
+      d = x.__send__(:delta)
+      return (self << d.imag) - d.real
+    end
+    raise TypeError, 'expected numeric'
+  end
+
+end
+
+$VERBOSE = vsave