That’s like 12 x 30 x ¥35000 = 12600000 yen. ＄84000. I don’t know about others, but I consider myself pretty well off and I do not have that kind of money.
That's too low.
The National Basic Pension is around 60,000 yen per month and with traditional employer part on top (not everyone has it), it's 140,000 yen/month. I would think a foreigner immigrant would need to bring the equivalent of around $160k in a retirement savings account or similar.
I very much doubt they count any employer pension toward that because people that get that don’t need the money themselves.