--- lib/encodings.c
+++ lib/encodings.c	2012-10-01 14:42:07.895867558 +0000
@@ -224,6 +224,7 @@ static struct charset_entry charset_tabl
 	{ "EUC-CN",		"nippon"	},
 	{ "EUC-JP",		"nippon"	},
 	{ "EUC-TW",		"nippon"	},
+	{ "GB18030",		"nippon"	},
 	{ "GBK",		"nippon"	},
 # else /* !MULTIBYTE_GROFF */
 	/* If we have a smarter version of groff, this is better dealt with
@@ -311,6 +312,7 @@ static struct less_charset_entry less_ch
 
 #ifdef MULTIBYTE_GROFF
 	{ "CP1251",		"windows",	NULL		},
+	{ "GB18030",		"zh",		NULL		},
 	{ "EUC-JP",		"iso8859",	"japanese-ujis"	},
 	{ "KOI8-R",		"koi8-r",	NULL		},
 	/* close enough? */
@@ -502,6 +504,13 @@ char *get_page_encoding (const char *lan
  *     roff encoding = ISO-8859-15
  *     output encoding = ISO-8859-15
  *     ISO-8859-15 -> groff -Tascii8 -> ISO-8859-15 -> iconv -> UTF-8
+ *
+ *   /usr/share/man/zh_CN.GB18030, locale zh_CN.UTF-8
+ *     page encoding = GB18030
+ *     source encoding = GB18030
+ *     roff encoding = UTF-8
+ *     output encoding = UTF-8
+ *     GB18030 -> iconv -> UTF-8 -> groff -Tutf8 -> UTF-8
  */
 const char *get_source_encoding (const char *lang)
 {
@@ -654,7 +663,7 @@ static int compatible_encodings (const c
 	 */
 	if ((STREQ (input, "BIG5") || STREQ (input, "BIG5HKSCS") ||
 	     STREQ (input, "EUC-JP") ||
-	     STREQ (input, "EUC-CN") || STREQ (input, "GBK") ||
+	     STREQ (input, "EUC-CN") || STREQ (input, "GB18030") || STREQ (input, "GBK") ||
 	     STREQ (input, "EUC-KR") ||
 	     STREQ (input, "EUC-TW")) &&
 	    STREQ (output, "UTF-8"))
@@ -758,7 +767,7 @@ const char *get_roff_encoding (const cha
 		    STRNEQ (ctype, "zh_HK", 5) ||
 		    STRNEQ (ctype, "zh_SG", 5) ||
 		    STRNEQ (ctype, "zh_TW", 5))
-			roff_encoding = "UTF-8";
+			roff_encoding = source_encoding; /* "UTF-8"; */
 	}
 #endif /* MULTIBYTE_GROFF */