modern Japanese writing; contemporary text
Refers to texts written in modern Japanese, typically from the Meiji period onward, as opposed to classical Japanese (古文).
This novel is written in modern Japanese, so it's easy to read.
modern Japanese (school subject)
A subject in Japanese schools focusing on reading and analyzing modern Japanese texts, often contrasted with 古文 (classical Japanese) and 漢文 (classical Chinese).
In high school modern Japanese class, we read works by Natsume Soseki.