What happens if you don’t pay the pension for 8 years?

I’ve lived in Japan for 8 years and never paid the pension. I’ve never been enrolled, so I’ve never received any invoice or letter.

The first year I was on a Working Holiday Visa, so I didn’t enroll, and I was working part time.

The second and third years I was on a Student Visa, also working part time. Around this time I heard it was compulsory to enroll, even if you ask for an exemption or reduction, but I was a student living day by day and I was not planning to stay this long, so I just didn’t enroll.

From the fourth year to now, I’ve been working as a freelancer for an English school. I’ve been paying from the beginning for the National Health insurance, resident tax, and of course get 10% deducted from my ‘salary’.

Now I want to change jobs because my boss is power harassing the employees, but I’m worried if I go to another school, I will get the regular employee contract and be enrolled in the pension.

A friend was unemployed for a year and still got a letter saying that she had to pay ¥400.000 for that year, she was temporarily out of Japan.

So, how much money could it be for 8 years? My salary was less than ¥200,000 the first four years and ¥300,000 the last four years.

Should I just change jobs and then when I get the letter from the pension system hire a lawyer?

I would appreciate your help. Thank you very much!