Nishimura Kyotaro Memorial Museum Coffee Cup

This is a coffee cup from the Kyotaro Nishimura Memorial Museum.
This is just my guess, but there was an event in 2012 celebrating 500 books, so perhaps it was given to attendees? Or maybe it was just sold at the museum. I don't know any more details.
I've listed it as near unused, but it's probably unused. The box has some minor damage.

The coffee cup itself has no manufacturer's mark. The signature is printed on a plain white background.

The card attached to the box is handwriting-style print.
The hexagonal mark was likely from a flower-shaped ribbon with adhesive tape, but I don't remember clearly.

I apologize, but please refrain from price reductions or holds.
Please understand that this is a stored item from a private home, not something recently purchased.

Due to my irregular work schedule, shipping may take up to 5 days.

Thank you for your understanding.