Holy Multiple Posts, Batman!
Welcome (x11) to BC and to the thread, @pbmuenchen and thanks for the pics & video of your bass.
Always interesting to see another one - everything we know about these is in this thread, and unfortunately it's not very much! Mid '80s, made in Japan, probably at the Chushin Gakki factory, and a fairly uncommon model.
If there's more to be found out, I think the Washburn Guitars - The Golden Era group would be the best place to look!