What I don't like about this is that the field clearly says "period of stay" and then the *instructions* say to enter something different. The problem is, the instructions can disappear, then later they can be like: well, you entered incorrect information.
I know in reality this is just a design oversight that in true Rakuten style they solved with a FAQ entry, but still...
Also, they ask for a Katakana name, which is not a field on the card anyway.