The Justice Ministry will impose new regulations on Japanese-language schools in October to ensure students who enter Japan to learn the language do not spend the majority of their stay working instead of studying.

The change was implemented after one applicant raised the ministry’s eyebrows by asking about setting up a school that would be in session for just half a year, presumably so students could use the longer holiday period to work.

Under current student visa conditions, students can work up to 40 hours a week when their schools are on holiday and 28 hours when they are in session. Although there were previously no rules on how long a school should be in session, the new rule will require schools to be in session for at least 35 weeks a year.

“The main duty of a student is to study,” said Justice Ministry official Tetsuya Soga, who explained that the new rule is intended as a way to clarify that students should be putting their effort into studying rather than working.

“Studying abroad in Japan is not the equivalent of a work visa,” Soga said.

The current rules, which require schools to hold at least 760 classes per year and 20 classes per week, with each class running a minimum of 45 minutes, will remain unchanged.

There were some 78,000 students enrolled at Japanese schools as of May 2017, according to a report published in December by the Japan Student Services Organization. The figure represents a threefold increase over six years from 25,000 in 2011, when record-keeping began.

A separate study by the Association for the Promotion of Japanese Language Education published in 2010 showed that some 70 percent of students surveyed were working part-time while studying. The study also showed that students worked an average of roughly 15 hours a week.

Unlike universities, which must be established by an educational corporation, Japanese schools can be set up by individuals and business corporations as long as the rules laid down by the Justice Ministry are complied with.

Other major revisions to the rules state that school principals cannot head up more than two schools at once and must elect a vice principal if they are managing two schools.