You would be on the "Engineer/Specialist in Humanities/International Services" visa, assuming you intend to work in IT.
I wasn't 100% sure if an associate degree is "enough" to satisfy the requirements, but based on this third party immigration advisor's website, it seems that that is still acceptable:
You have graduated from university or college (obtaining Bachelor, License or Associate degree or more) specializing in the field of Social Science or Humanities which relates to your intended work in Japan.
It goes on to say that you need to satisfy the same for the Engineer visa, so it does seem like an associate degree is likely to be sufficient.
Additionally, Tokyo Dev (an English language job board for tech jobs) states:
"In my experience, an Associate Degree has a high chance of being accepted, while a Diploma or Certificate has a high chance of being rejected."
The degree must also be related to engineering. As the “Engineer” designation is used for positions that require knowledge of technology, physical science, natural science, or engineering, a degree related to any of these topics could theoretically be used to obtain a visa as a software engineer.
That said, it does say the following:
So if you have a degree like a Bachelor’s or Master’s, it is clear you’re eligible for a visa, but otherwise eligibility will be determined on a case-by-case basis.
This suggests it might be more challenging to be accepted, but given your existing work experience in the field, I expect that you'll have a stronger case than just a fresh graduate with an associate degree.
If you don't have luck with this route, there is also the ITPEC exam, which proves your skills. More info.