diff --git a/translations/ja_JP.ts b/translations/ja_JP.ts
index 931c1907a..1db85ec2b 100644
--- a/translations/ja_JP.ts
+++ b/translations/ja_JP.ts
@@ -1270,7 +1270,7 @@
     </message>
     <message>
         <source>Optimize Database</source>
-        <translation></translation>
+        <translation>データベースの最適化</translation>
     </message>
     <message>
         <source>Open link in current tab</source>
diff --git a/windows/languages.nsh b/windows/languages.nsh
index 2328fec46..03e9f1037 100644
--- a/windows/languages.nsh
+++ b/windows/languages.nsh
@@ -1,4 +1,4 @@
-;;;;English
+;;;;English
 LangString TITLE_SecMain ${LANG_ENGLISH} "Main Components"
 LangString TITLE_SecTranslations ${LANG_ENGLISH} "Translations"
 LangString TITLE_SecPlugins ${LANG_ENGLISH} "Plugins"
@@ -258,6 +258,27 @@ LangString DESC_SecDesktop ${LANG_GEORGIAN} "გამშვების და
 LangString DESC_SecExtensions ${LANG_GEORGIAN} "QupZilla-ს ასოცირება .htm და .html ფაილებთან"
 LangString DESC_SecThemes ${LANG_GEORGIAN} "დამატებითი თემები QupZilla-სთვის"
 
+;;;;JAPANESE
+LangString TITLE_SecMain ${LANG_JAPANESE} "メインコンポーネント"
+LangString TITLE_SecTranslations ${LANG_JAPANESE} "翻訳ファイル"
+LangString TITLE_SecPlugins ${LANG_JAPANESE} "プラグイン(拡張機能)"
+LangString TITLE_SecExamplePlugin ${LANG_JAPANESE} "Example Plugin"
+LangString TITLE_SecDesktop ${LANG_JAPANESE} "デスクトップアイコン"
+LangString TITLE_SecExtensions ${LANG_JAPANESE} "ファイルの関連付け"
+LangString TITLE_SecThemes ${LANG_JAPANESE} "テーマ"
+
+LangString FILE_Htm ${LANG_JAPANESE} "HTMファイル"
+LangString FILE_Html ${LANG_JAPANESE} "HTMLファイル"
+;
+LangString DESC_SecMain ${LANG_JAPANESE} "アプリケーションのメインとなる部分です。"
+LangString DESC_SecTranslations ${LANG_JAPANESE} "他の言語でもQupZillaを使えるようになります。デフォルトでは英語です。"
+LangString DESC_SecPlugins ${LANG_JAPANESE} "プラグイン(拡張機能)を追加してダウンロードします"
+LangString DESC_SecExamplePlugin ${LANG_JAPANESE} "テスト用のプラグインです."
+LangString DESC_SecDesktop ${LANG_JAPANESE} "デスクトップにアイコンを作成します."
+LangString DESC_SecExtensions ${LANG_JAPANESE} "QupZillaにhtm、htmlファイルを関連付けます。"
+LangString DESC_SecThemes ${LANG_JAPANESE} "QupZillaのデフォルトテーマ以外のテーマをダウンロードします。"
+
+
 ;;;;;;;;;
 ;;;;;;;;;
 ; Unfinished translations
@@ -333,4 +354,4 @@ LangString TITLE_SecThemes ${LANG_SWEDISH} "Themes"
 LangString DESC_SecThemes ${LANG_KOREAN} "Additional themes for QupZilla"
 LangString DESC_SecThemes ${LANG_RUSSIAN} "Additional themes for QupZilla"
 LangString DESC_SecThemes ${LANG_SPANISH} "Additional themes for QupZilla"
-LangString DESC_SecThemes ${LANG_SWEDISH} "Additional themes for QupZilla"
+LangString DESC_SecThemes ${LANG_SWEDISH} "Additional themes for QupZilla"
\ No newline at end of file