diff --git a/docs/manpage.rst b/docs/manpage.rst
index 543d1dbad0faf1d8052aa4c125b5e7df3ee1fc0a..a2ccd9e2a34d6754cf2d603f8f152a8ddc4f67e8 100644
--- a/docs/manpage.rst
+++ b/docs/manpage.rst
@@ -66,6 +66,11 @@ options
   ``--version``
     output version information and exit.
 
+``Arguments related to `realdice' randomsource:``
+
+   ``--dice-sides`` `N`
+   Number of sides of dice. Default: 6
+
 
 copyright
 ---------