Adding the priority 10 in the remove_filter for relevanssi_query is useless. 10 is the default and this is the priority it has been added with.
It took while to find the right place.
That was in the functions.php file.
I just added the below code and that made the trick:
if (ICL_LANGUAGE_CODE == 'ja') {
remove_filter('the_posts', 'relevanssi_query');
remove_filter('posts_request', 'relevanssi_prevent_default_request',9);
remove_filter('query_vars', 'relevanssi_query_vars');
}
Thanks