There are a number of ways to train for a Jinja Honchō priest’s license: there are courses at the two Shinto universities (Kokugakuin and Kōgakkan), there are intensive courses held across the country, and there are courses at six training centres. The courses at these training centres normally run for two years, and qualify you for Seikai, the middle rank of Shinto priests, and a sufficient qualification to be the chief priest of an ordinary jinja. However, at most of them you can also take the course for one year, which gets you Gon-no-Seikai, one rank lower, but still enough to be chief priest of an ordinary jinja. These are all small; three of them take a maximum of ten students per year, and the largest takes a maximum of twenty. However, judging from the reported numbers of graduates, they are almost never full. As a basic rule, they require you to have graduated for high school, and most of them have an upper age limit, which ranges from 21 to 30.
All six advertise together in Jinja Shinpō, and the table describing their courses has a row for “special characteristics”.
Shiwahiko Jinja Shiogama Jinja Priest Training Centre is in Shiogama, near Sendai in Miyagi prefecture, north-east Japan. They emphasise the union of theory and practice, teaching how to perform gagaku (traditional music) and run a jinja, as well as the theory of Shinto.
Dewa Sanzan Jinja Priest Training Centre is in Yamagata prefecture, on the northern Japan Sea coast. As well as participation in many of the matsuri at the jinja, it also offers participation in the Shugendō(-derived) ceremonies that are still performed at the jinja.
Jingū Training Centre is at Jingū, in Isë, central Japan. It is unique in that it only takes men. The main selling point here is that you get to serve in the matsuri at Jingū, but they also call out the fact that they will teach you how to use a computer.
Atsuta Jingū College is in Nagoya, central Japan. If you train with them you will not only become a priest, but also a qualified boy scout leader, and the college pays the necessary expenses for this qualification.
Kyoto Kokugakuin is in Yawata and Kyoto. They offer to accommodate everyone in their dormitory, which is in the grounds of Iwashimizu Hachimangū, a famous and important jinja south of Kyoto. You serve in the jinja in the morning, and then go into the school in the city in the afternoon for academic courses. You also have the opportunity to serve at four of the most famous matsuri in the country (the Iwashimizu Matsuri, the Kamo Matsuri, the Kasuga Matsuri, and the Jidai Matsuri). You may, if you wish, qualify as a scout leader, and the school will introduce jinja for you to work at if necessary.
Taisha (or possibly Ōyashiro) Kokugakuin is in Izumo, in Shimanë prefecture. It is associated with Izumo Ōyashiro, which is why I am not entirely sure how to read the name of the training centre. This centre also has a dormitory that can accommodate everyone, and emphasises the teaching of both practical and academic skills, including jinja music, calligraphy, English conversation, and information processing. They also have study trips.
However, my impression from the numbers is that only a small minority of priests train at one of these centres. Most either do a four year course at the university, or an intensive course to get the qualification necessary to serve at their family jinja. Personally, I think this is a shame, as the diversity of the centres suits the fundamental diversity of Shinto.