diff --git a/ChangeLog b/ChangeLog
index 6a5705f7c8..4ecf840897 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed Mar  9 11:53:31 2011  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* enc/shift_jis.c: Change SJIS as an alias of Windows-31J.
+
+	* enc/shift_jis.c: Add PCK as an alias of Windows-31J.
+
 Wed Mar  9 00:45:29 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* ext/extmk.rb: nmake substitutes all occurences in macro.
diff --git a/enc/shift_jis.c b/enc/shift_jis.c
index b8ca67dba1..cb07cfe081 100644
--- a/enc/shift_jis.c
+++ b/enc/shift_jis.c
@@ -382,7 +382,6 @@ OnigEncodingDefine(shift_jis, Shift_JIS) = {
  * Link: http://www.iana.org/assignments/character-sets
  * Link: http://ja.wikipedia.org/wiki/Shift_JIS
  */
-ENC_ALIAS("SJIS", "Shift_JIS")
 
 /*
  * Name: Windows-31J
@@ -391,10 +390,27 @@ ENC_ALIAS("SJIS", "Shift_JIS")
  * Link: http://www.microsoft.com/globaldev/reference/dbcs/932.mspx
  * Link: http://ja.wikipedia.org/wiki/Windows-31J
  * Link: http://source.icu-project.org/repos/icu/data/trunk/charset/data/ucm/windows-932-2000.ucm
+ *
+ * Windows Standard Character Set and its mapping to Unicode by Microsoft.
+ * Since 1.9.3, SJIS is the alias of Windows-31J because its character
+ * set is usually this one even if its mapping may differ.
  */
 ENC_REPLICATE("Windows-31J", "Shift_JIS")
 ENC_ALIAS("CP932", "Windows-31J")
 ENC_ALIAS("csWindows31J", "Windows-31J") /* IANA.  IE6 don't accept Windows-31J but csWindows31J. */
+ENC_ALIAS("SJIS", "Windows-31J")
+
+/*
+ * Name: PCK
+ * Link: http://download.oracle.com/docs/cd/E19253-01/819-0606/x-2chn0/index.html
+ * Link: http://download.oracle.com/docs/cd/E19253-01/819-0606/appb-pckwarn-1/index.html
+ *
+ * Solaris's SJIS variant. Its set is Windows Standard Character Set; it
+ * consists JIS X 0201 Latin (US-ASCII), JIS X 0201 Katakana, JIS X 0208, NEC
+ * special characters, NEC-selected IBM extended characters, and IBM extended
+ * characters. Solaris's iconv seems to use SJIS-open.
+ */
+ENC_ALIAS("PCK", "Windows-31J")
 
 /*
  * Name: MacJapanese