Having studied in Japan for two years, I have tried a variety of part-tme jobs from a convenient store staff, prep chef at a restaurant, all the way to an interpreter at a technical trainee center, doing an internship at Yamaha and being a research assistant at my university. All the different type of jobs do vary in wages, but I can say that the best and the most effortless way to finance your study in Japan is with scholarships.
During my first hike to Mount Fuji in 2023, I was almost stranded on the summit without shelter with temperature near 0°C at midnight. I hope by sharing this experience, it will help others hiking mount Fuji better prepare for it in the future.