Originally Posted by in4tar

I tried the codes, the result was "this rate is not available". But didn't realize that $100 credit has anything to do with the room you book.

I didn't ask to discount my room rate by $100. I just called and asked if I can use $100 credit (for, let's say, dining in the hotel) and was told that to be able to use this $100 credit at all, I need to book a more expensive room.
Funny, it's not even the cheapest room at RC Kyoto that I booked - it's their "water view luxury double". Still...