diff --git a/doc/man/ja/mkvextract.1 b/doc/man/ja/mkvextract.1
index 1f8a54082..4a7698c5d 100644
--- a/doc/man/ja/mkvextract.1
+++ b/doc/man/ja/mkvextract.1
@@ -2,12 +2,12 @@
 .\"     Title: mkvextract
 .\"    Author: Bunkus Moritz[FAMILY Given] <moritz@bunkus.org>
 .\" Generator: DocBook XSL Stylesheets v1.75.1 <http://docbook.sf.net/>
-.\"      Date: January 2010
+.\"      Date: 2010年1月
 .\"    Manual:  
 .\"    Source: MkvToolNix 3.1.0
 .\"  Language: Japanese
 .\"
-.TH "MKVEXTRACT" "1" "January 2010" "MkvToolNix 3\&.1\&.0" ""
+.TH "MKVEXTRACT" "1" "2010年1月" "MkvToolNix 3\&.1\&.0" ""
 .\" -----------------------------------------------------------------
 .\" * set default formatting
 .\" -----------------------------------------------------------------
diff --git a/doc/man/ja/mkvinfo.1 b/doc/man/ja/mkvinfo.1
index bc448ce01..51a766a6d 100644
--- a/doc/man/ja/mkvinfo.1
+++ b/doc/man/ja/mkvinfo.1
@@ -2,12 +2,12 @@
 .\"     Title: mkvinfo
 .\"    Author: Bunkus Moritz[FAMILY Given] <moritz@bunkus.org>
 .\" Generator: DocBook XSL Stylesheets v1.75.1 <http://docbook.sf.net/>
-.\"      Date: January 2010
+.\"      Date: 2010年1月
 .\"    Manual:  
 .\"    Source: MkvToolNix 3.1.0
 .\"  Language: Japanese
 .\"
-.TH "MKVINFO" "1" "January 2010" "MkvToolNix 3\&.1\&.0" ""
+.TH "MKVINFO" "1" "2010年1月" "MkvToolNix 3\&.1\&.0" ""
 .\" -----------------------------------------------------------------
 .\" * set default formatting
 .\" -----------------------------------------------------------------
diff --git a/doc/man/ja/mkvmerge.1 b/doc/man/ja/mkvmerge.1
index e867a186c..742cfe41c 100644
--- a/doc/man/ja/mkvmerge.1
+++ b/doc/man/ja/mkvmerge.1
@@ -2,12 +2,12 @@
 .\"     Title: mkvmerge
 .\"    Author: Bunkus Moritz[FAMILY Given] <moritz@bunkus.org>
 .\" Generator: DocBook XSL Stylesheets v1.75.1 <http://docbook.sf.net/>
-.\"      Date: January 2010
+.\"      Date: 2010年1月
 .\"    Manual:  
 .\"    Source: MkvToolNix 3.1.0
 .\"  Language: Japanese
 .\"
-.TH "MKVMERGE" "1" "January 2010" "MkvToolNix 3\&.1\&.0" ""
+.TH "MKVMERGE" "1" "2010年1月" "MkvToolNix 3\&.1\&.0" ""
 .\" -----------------------------------------------------------------
 .\" * set default formatting
 .\" -----------------------------------------------------------------
diff --git a/doc/man/ja/mkvpropedit.1 b/doc/man/ja/mkvpropedit.1
index 02f88f9e0..fc4cf9dfb 100644
--- a/doc/man/ja/mkvpropedit.1
+++ b/doc/man/ja/mkvpropedit.1
@@ -2,12 +2,12 @@
 .\"     Title: mkvpropedit
 .\"    Author: Bunkus Moritz[FAMILY Given] <moritz@bunkus.org>
 .\" Generator: DocBook XSL Stylesheets v1.75.1 <http://docbook.sf.net/>
-.\"      Date: January 2010
+.\"      Date: 2010年1月
 .\"    Manual:  
 .\"    Source: MkvToolNix 3.1.0
 .\"  Language: Japanese
 .\"
-.TH "MKVPROPEDIT" "1" "January 2010" "MkvToolNix 3\&.1\&.0" ""
+.TH "MKVPROPEDIT" "1" "2010年1月" "MkvToolNix 3\&.1\&.0" ""
 .\" -----------------------------------------------------------------
 .\" * set default formatting
 .\" -----------------------------------------------------------------
diff --git a/doc/man/ja/mmg.1 b/doc/man/ja/mmg.1
index b31dc1d09..4cc3900de 100644
--- a/doc/man/ja/mmg.1
+++ b/doc/man/ja/mmg.1
@@ -2,12 +2,12 @@
 .\"     Title: mmg
 .\"    Author: Bunkus Moritz[FAMILY Given] <moritz@bunkus.org>
 .\" Generator: DocBook XSL Stylesheets v1.75.1 <http://docbook.sf.net/>
-.\"      Date: January 2010
+.\"      Date: 2010年1月
 .\"    Manual:  
 .\"    Source: MkvToolNix 3.1.0
 .\"  Language: Japanese
 .\"
-.TH "MMG" "1" "January 2010" "MkvToolNix 3\&.1\&.0" ""
+.TH "MMG" "1" "2010年1月" "MkvToolNix 3\&.1\&.0" ""
 .\" -----------------------------------------------------------------
 .\" * set default formatting
 .\" -----------------------------------------------------------------