I got a 50 sen note 1945 recently. It is P59. In the description of the note the lettering block does not have the extreme right hand character that can be seen in the image. It looks like many Japanese notes from the war period have the same lettering block. It is incorrect. I suspect the symbol indicates "Greater" as it is after the symbols for Japan, Nippon.

Ah, I don't know why I over-read this. Yes, their is a ‘dai’ to much, I removed it.