diff --git a/include/rapidjson/encodings.h b/include/rapidjson/encodings.h
index dcf21e4..fd8689d 100644
--- a/include/rapidjson/encodings.h
+++ b/include/rapidjson/encodings.h
@@ -23,6 +23,8 @@ namespace rapidjson {
 concept Encoding {
 	typename Ch;	//! Type of character. A "character" is actually a code unit in unicode's definition.
 
+	enum { supportUnicode = 1 }; // or 0 if not supporting unicode
+
 	//! \brief Encode a Unicode codepoint to an output stream.
 	//! \param os Output stream.
 	//! \param codepoint An unicode codepoint, ranging from 0x0 to 0x10FFFF inclusively.
@@ -78,6 +80,8 @@ template<typename CharType = char>
 struct UTF8 {
 	typedef CharType Ch;
 
+	enum { supportUnicode = 1 };
+
 	template<typename OutputStream>
 	static void Encode(OutputStream& os, unsigned codepoint) {
 		if (codepoint <= 0x7F) 
@@ -222,6 +226,8 @@ struct UTF16 {
 	typedef CharType Ch;
 	RAPIDJSON_STATIC_ASSERT(sizeof(Ch) >= 2);
 
+	enum { supportUnicode = 1 };
+
 	template<typename OutputStream>
 	static void Encode(OutputStream& os, unsigned codepoint) {
 		RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputStream::Ch) >= 2);
@@ -351,6 +357,8 @@ struct UTF32 {
 	typedef CharType Ch;
 	RAPIDJSON_STATIC_ASSERT(sizeof(Ch) >= 4);
 
+	enum { supportUnicode = 1 };
+
 	template<typename OutputStream>
 	static void Encode(OutputStream& os, unsigned codepoint) {
 		RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputStream::Ch) >= 4);
@@ -447,6 +455,66 @@ struct UTF32BE : UTF32<CharType> {
 	}
 };
 
+///////////////////////////////////////////////////////////////////////////////
+// ASCII
+
+//! ASCII encoding.
+/*! http://en.wikipedia.org/wiki/ASCII
+	\tparam CharType Code unit for storing 7-bit ASCII data. Default is char.
+	\note implements Encoding concept
+*/
+template<typename CharType = char>
+struct ASCII {
+	typedef CharType Ch;
+
+	enum { supportUnicode = 0 };
+
+	template<typename OutputStream>
+	static void Encode(OutputStream& os, unsigned codepoint) {
+		RAPIDJSON_ASSERT(codepoint <= 0x7F);
+		os.Put(static_cast<Ch>(codepoint & 0xFF));
+	}
+
+	template <typename InputStream>
+	static bool Decode(InputStream& is, unsigned* codepoint) {
+		unsigned char c = static_cast<unsigned char>(is.Take());
+		*codepoint = c;
+		return c <= 0X7F;
+	}
+
+	template <typename InputStream, typename OutputStream>
+	static bool Validate(InputStream& is, OutputStream& os) {
+		unsigned char c = is.Take();
+		os.Put(c);
+		return c <= 0x7F;
+	}
+
+	template <typename InputByteStream>
+	static CharType TakeBOM(InputByteStream& is) {
+		RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
+		Ch c = Take(is);
+		return c;
+	}
+
+	template <typename InputByteStream>
+	static Ch Take(InputByteStream& is) {
+		RAPIDJSON_STATIC_ASSERT(sizeof(typename InputByteStream::Ch) == 1);
+		return is.Take();
+	}
+
+	template <typename OutputByteStream>
+	static void PutBOM(OutputByteStream& os) {
+		RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
+		(void)os;
+	}
+
+	template <typename OutputByteStream>
+	static void Put(OutputByteStream& os, Ch c) {
+		RAPIDJSON_STATIC_ASSERT(sizeof(typename OutputByteStream::Ch) == 1);
+		os.Put(static_cast<typename OutputByteStream::Ch>(c));
+	}
+};
+
 ///////////////////////////////////////////////////////////////////////////////
 // AutoUTF
 
diff --git a/include/rapidjson/writer.h b/include/rapidjson/writer.h
index f3b7567..73677c1 100644
--- a/include/rapidjson/writer.h
+++ b/include/rapidjson/writer.h
@@ -256,7 +256,39 @@ protected:
 		GenericStringStream<SourceEncoding> is(str);
 		while (is.Tell() < length) {
 			const Ch c = is.Peek();
-			if ((sizeof(Ch) == 1 || (unsigned)c < 256) && escape[(unsigned char)c])  {
+			if (!TargetEncoding::supportUnicode && (unsigned)c >= 0x80) {
+				// Unicode escaping
+				unsigned codepoint;
+				if (!SourceEncoding::Decode(is, &codepoint))
+					return false;
+				os_.Put('\\');
+				os_.Put('u');
+				if (codepoint <= 0xD7FF || (codepoint >= 0xE000 && codepoint <= 0xFFFF)) {
+					os_.Put(hexDigits[(codepoint >> 12) & 15]);
+					os_.Put(hexDigits[(codepoint >>  8) & 15]);
+					os_.Put(hexDigits[(codepoint >>  4) & 15]);
+					os_.Put(hexDigits[(codepoint      ) & 15]);
+				}
+				else if (codepoint >= 0x010000 && codepoint <= 0x10FFFF)	{
+					// Surrogate pair
+					unsigned s = codepoint - 0x010000;
+					unsigned lead = (s >> 10) + 0xD800;
+					unsigned trail = (s & 0x3FF) + 0xDC00;
+					os_.Put(hexDigits[(lead >> 12) & 15]);
+					os_.Put(hexDigits[(lead >>  8) & 15]);
+					os_.Put(hexDigits[(lead >>  4) & 15]);
+					os_.Put(hexDigits[(lead      ) & 15]);
+					os_.Put('\\');
+					os_.Put('u');
+					os_.Put(hexDigits[(trail >> 12) & 15]);
+					os_.Put(hexDigits[(trail >>  8) & 15]);
+					os_.Put(hexDigits[(trail >>  4) & 15]);
+					os_.Put(hexDigits[(trail      ) & 15]);					
+				}
+				else
+					return false;	// invalid code point
+			}
+			else if ((sizeof(Ch) == 1 || (unsigned)c < 256) && escape[(unsigned char)c])  {
 				is.Take();
 				os_.Put('\\');
 				os_.Put(escape[(unsigned char)c]);
diff --git a/test/unittest/writertest.cpp b/test/unittest/writertest.cpp
index be3d77b..b9a4891 100644
--- a/test/unittest/writertest.cpp
+++ b/test/unittest/writertest.cpp
@@ -113,13 +113,34 @@ TEST(Writer,DoublePrecision) {
 }
 
 TEST(Writer, Transcode) {
+	const char json[] = "{\"hello\":\"world\",\"t\":true,\"f\":false,\"n\":null,\"i\":123,\"pi\":3.1416,\"a\":[1,2,3],\"dollar\":\"\x24\",\"cents\":\"\xC2\xA2\",\"euro\":\"\xE2\x82\xAC\",\"gclef\":\"\xF0\x9D\x84\x9E\"}";
+
 	// UTF8 -> UTF16 -> UTF8
-	StringStream s("{ \"hello\" : \"world\", \"t\" : true , \"f\" : false, \"n\": null, \"i\":123, \"pi\": 3.1416, \"a\":[1, 2, 3], \"dollar\":\"\x24\", \"cents\":\"\xC2\xA2\", \"euro\":\"\xE2\x82\xAC\", \"gclef\":\"\xF0\x9D\x84\x9E\" } ");
-	StringBuffer buffer;
-	Writer<StringBuffer, UTF16<>, UTF8<> > writer(buffer);
-	GenericReader<UTF8<>, UTF16<> > reader;
-	reader.Parse<0>(s, writer);
-	EXPECT_STREQ("{\"hello\":\"world\",\"t\":true,\"f\":false,\"n\":null,\"i\":123,\"pi\":3.1416,\"a\":[1,2,3],\"dollar\":\"\x24\",\"cents\":\"\xC2\xA2\",\"euro\":\"\xE2\x82\xAC\",\"gclef\":\"\xF0\x9D\x84\x9E\"}", buffer.GetString());
+	{
+		StringStream s(json);
+		StringBuffer buffer;
+		Writer<StringBuffer, UTF16<>, UTF8<> > writer(buffer);
+		GenericReader<UTF8<>, UTF16<> > reader;
+		reader.Parse(s, writer);
+		EXPECT_STREQ(json, buffer.GetString());
+	}
+
+	// UTF8 -> UTF8 -> ASCII -> UTF8 -> UTF8
+	{
+		StringStream s(json);
+		StringBuffer buffer;
+		Writer<StringBuffer, UTF8<>, ASCII<> > writer(buffer);
+		Reader reader;
+		reader.Parse(s, writer);
+
+		StringBuffer buffer2;
+		Writer<StringBuffer> writer2(buffer2);
+		GenericReader<ASCII<>, UTF8<> > reader2;
+		StringStream s2(buffer.GetString());
+		reader2.Parse(s2, writer2);
+
+		EXPECT_STREQ(json, buffer2.GetString());
+	}
 }
 
 #include <sstream>