Japanese translation is added for Rukovoditel 1.6
http://rukovoditel.net/translations.php
This is last week of testing 1.6 beta and it will be released
Note: language file is required to update if you use extra translation and want to update to 1.6. So users who use extra translation can start update it for 1.6.
Updated instruction you can find on this page
http://rukovoditel.net/translations.php