What's the plural form of uta monogatari? Here's the word you're looking for.
Answer
The noun uta monogatari can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be uta monogatari.
However, in more specific contexts, the plural form can also be uta monogatari e.g. in reference to various types of uta monogatari
or a collection of uta monogatari.