Happy to answer, though sadly I can't say that there is any secret widespread ML organizations that you missed.

I think it's not quite true to say that there are no Marxist-Leninists in contemporary Japan (I am one!) but that they are at a much more grassroots level. In local circles and academic circles, I see a lot more of it. Members of the party that are winning seats in government, much less so.

I will say that your perception of the parties as a whole are accurate though. It isn't the same party that it was under Fuwa. The Kyosanto of today does lean pretty socdem in a lot of ways, as they ran away from a lot of their fouding principles after the red purge. The sudden 180 support of the Emperor is a particular sticking point for me recently, because they used to be very staunchly against the imperial family. The desire to distance themselves from the CPC also seems short-sighted, as they could easily be a great ally for us. There are many areas that the party needs work. It feels like constant concessions towards being practical has just served to undermine the party as a whole.

On the other hand, they do still have some good positions such as being opposed to the historical revisionism we see so often from Japanese politicians and being opposed to the US occupation. The latter of which I think is a necessary first step before basically anything else.

I would still encourage comrades here to reach out to their local chapters though, because I often find them much more left-oriented in their ways of thinking than the party as a whole might be. I think it is important to realise that a lot of the Kyosanto's run away from Marxism is very recent, within 20 years or less. There are a lot of members who predate that and still believe in a lot of core marxist tenants. I don't think it is out of the question for the party to course correct, but it will take a lot of effort.