Dear Dragan,

Thanks a lot for your patience. Your Kanban is talking about a medicine.
It is a sign advertising Kinapirin キナピリン 'very effective for fever and cold'

There is a blog about the subject:

https://ameblo.jp/usakokameko/entry-12487687646.html

Its in Japanese language though.

I believe the Kanban was used in 1930 / 1950 and is really nice vintage condition. It is hard to put a pricetag on it so I will do it with my Gut feeling. Estimation is based on what I believe it should me worth in an auction or sales room. Below that price I would not sell it if I were you.

Regards,

Simon Breider