How to use two adjectives on a single noun?

Question

e.g:

聞【き】いたところ、日本【にほん】は綺麗【きれい】な静【しず】かな国【くに】です。

Is the above correct, since 綺麗【きれい】な and 静【しず】かな are used together?

Answer 1

In such a case you put the first (I guess all but last, actually) adjective in the て form. For なadjectives this means replacing な by で, for い adjectives - replacing い by くて.

That is, in your example

。。。きれいで静かな国

https://www.learn-japanese-adventure.com/japanese-adjectives-2.html

Answer 2

The first adjective has to be in て-form.
な for na-adjectives turns into で.
い for i-adjectives turns into くて.
の for no-adjectives turns into で.

To connect the two to the noun that follows it, use the copula of the last adjective in the adjectival phrase. For example, if the second adjective you list is a no-adjective, then use the no-copula to connect to the noun.

Therefore, to answer your question, you would just have to swap 綺麗な for 綺麗で, since it's a na-adjective. The second na stays.

More things to look out for:

• 連体詞{れんたいし}(rentaishi).
  They can be forms of some number of i-adjectives which have an integrated attributive な. These forms are not inflectable. The rentaishi of 大きい is 大きな. Other interesting examples of rentaishi are the kosoado kotoba その,あの,どの etc.
  Since the copula is "part of their word", you cannot swap な for で in a list of adjectives. 大きな is never 大きで, since it's not a na-adjective. There are some guidelines (or even rules?) on when to use rentaishi over i-adjectives. You can read more here.

• Flat adverb modifying adjective.
  Two adjectives can follow each other directly without change: すごいでかい. Sugoi is an intensifying adjective: "'Extremely' big". すごい is used like an adverb here, modifying でかい, despite not being in adverbial form (すごく). Because this is odd, it's called 'Flat Adverb'. This mostly (or exclusively?) happens with intensifying adjectives.