Have you considered going back to finish college? You didn't mention when you dropped out but if you were almost finished, you enjoyed it and you are in a position where it's possible financially you might want to consider finishing it. While definitely not a requirement for tech, I considered not finishing my degree (I was receiving job offers for my "programming hobby" from everywhere and knew would not use my degree) but luckily I finished it; thanks to that I am able to live and work in Tokyo. I would not be able to do that had I had no official degree.
Does Japan not consider something like three years professional experience to be equivalent to one year of further education study? “Equivalent experience”?
College degree is a requirement for most work visas. Otherwise, you can show significant work experience, but from what I remember last I checked (been a few years since I looked into this), it's a significantly higher hurdle in terms of # of years.
