There was a 10% discount at the restaurant on the 5th floor for those staying in the hotel, but when my father had dinner there, the staffs didn't give him the discount. He presented his room key, but still was charged at full price.
When I got back to the hotel, I went to talk to the manager on duty and we got the price difference back.
The manager stated that it was a misunderstanding, because my father spoke only English, and their staffs are not proficient enough to understand him. I spoke to the manager in Japanese and got this settled.
The staffs' foreign language proficiency is disappointing. If you don't speak Japanese, I suggest you consider staying in another hotel.