diff --git a/ChangeLog b/ChangeLog
index 8292863633..6a59b5069e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+Sat Apr  6 00:19:30 2013  Hiroshi Shirosaki  <h.shirosaki@gmail.com>
+
+	* load.c (features_index_add): use rb_str_subseq() to specify C string
+	  position properly to fix require non ascii path.
+	  [ruby-core:53733] [Bug #8165]
+
+	* test/ruby/test_require.rb (TestRequire#test_require_nonascii_path):
+	  a test for the above.
+
 Fri Apr  5 20:41:49 2013  Tanaka Akira  <akr@fsij.org>
 
 	* include/ruby/defines.h (HAVE_TRUE_LONG_LONG): Defined to distinguish
diff --git a/load.c b/load.c
index 7c69461a8e..dab493da70 100644
--- a/load.c
+++ b/load.c
@@ -247,16 +247,16 @@ features_index_add(VALUE feature, VALUE offset)
 	if (p < feature_str)
 	    break;
 	/* Now *p == '/'.  We reach this point for every '/' in `feature`. */
-	short_feature = rb_str_substr(feature, p + 1 - feature_str, feature_end - p - 1);
+	short_feature = rb_str_subseq(feature, p + 1 - feature_str, feature_end - p - 1);
 	features_index_add_single(short_feature, offset);
 	if (ext) {
-	    short_feature = rb_str_substr(feature, p + 1 - feature_str, ext - p - 1);
+	    short_feature = rb_str_subseq(feature, p + 1 - feature_str, ext - p - 1);
 	    features_index_add_single(short_feature, offset);
 	}
     }
     features_index_add_single(feature, offset);
     if (ext) {
-	short_feature = rb_str_substr(feature, 0, ext - feature_str);
+	short_feature = rb_str_subseq(feature, 0, ext - feature_str);
 	features_index_add_single(short_feature, offset);
     }
 }
diff --git a/test/ruby/test_require.rb b/test/ruby/test_require.rb
index bca6a9754c..2e7b37d138 100644
--- a/test/ruby/test_require.rb
+++ b/test/ruby/test_require.rb
@@ -59,6 +59,27 @@ class TestRequire < Test::Unit::TestCase
     end
   end
 
+  def test_require_nonascii_path
+    bug8165 = '[ruby-core:53733] [Bug #8165]'
+    Dir.mktmpdir {|tmp|
+      encoding = /mswin|mingw/ =~ RUBY_PLATFORM ? 'filesystem' : 'UTF-8'
+      dir = "\u3042" * 5
+      begin
+        require_path = File.join(tmp, dir, 'foo.rb').encode(encoding)
+      rescue
+        skip "cannot convert path encoding to #{encoding}"
+      end
+      Dir.mkdir(File.dirname(require_path))
+      open(require_path, "wb") {}
+      assert_in_out_err([], <<-INPUT, %w(:ok), [], bug8165)
+        # coding: #{encoding}
+        $:.replace([IO::NULL] + $:.reject {|path| path !~ /\.ext/})
+        p :ok if require '#{require_path}'
+        p :ng if require '#{require_path}'
+      INPUT
+    }
+  end
+
   def test_require_path_home_1
     env_rubypath, env_home = ENV["RUBYPATH"], ENV["HOME"]
     pathname_too_long = /pathname too long \(ignored\).*\(LoadError\)/m