see Nikko and die; don't say 'wonderful' until you've seen Nikko
Proverb meaning that Nikko is so beautiful that one cannot truly appreciate splendor without seeing it. The literal sense is 'don't say kekkō (wonderful) until you've seen Nikko'. Often compared to the Italian saying 'see Naples and die'.
See also: ナポリを見てから死ね
There is a proverb: 'Don't say wonderful until you've seen Nikko.'