Yosuke Amaike, 39, spends a busy week juggling work at four different schools, where he works as a part-time instructor.

He gives lectures at Gifu University, as well as a private university, a junior college and a vocational school, and his salaries are decided according to the number of classes he holds.

For the current school year, which started in April, he has six classes a week in the first half of the year and five in the latter half, and the pay is roughly ¥10,000 per class.