Are doctorat students required to pass entrance tests like maths to study at Japanese universities?

I have recently learned that students who desire to study at Japanese Universities must have some entrance examinations such as science, maths, Japanese and English. But I'm just curious to know whether this is mainly required from prospective undergraduates or even graduate and doctorat students are required to have them too as major criteria to get their admission at Japanese universities? In case they must have them, do they have subjects based on their major, e.g. If a doctorat student want to pursue a PhD degree in cultural studies, what kind of test would he/she have?