Now, Japan has around 4 main school branches divided in as many as 50 schools and sub-schools, some of them labeled as new religions. We will discuss some of them here, and link to the main ones for a more indepth study of the major schools.
We first have to know that, in the world, there are three main schools of Buddhism:
The Theravāda or the Ancient Teaching (the oldest school in East-Asia)
The Mahāyāna or the great vehicule (principal school in Asia and Japan)
The Vajrayāna or diamond vehicule (Esoteric Buddhism including Tibetan and Shingon) also called Tantric Buddhism