Tori Kudo's blog may have some useful information. Browse the first few pages. I think he discusses his involvement in radical politics/terrorist groups and the early days of the Japanese underground a little bit.
http://elogedelamour.blogspot.com/
also...
Asahito Nanjo interview
http://www.squealermusic.com/reviews...interview.html
Munehiro Narita interview
http://www.squealermusic.com/reviews...interview.html
Fushitsusha interview (without Haino)
http://noise.as/fushitsusha
Keiji Haino interview
http://www.halana.com/haino.html
There's also a fairly extensive interview with Kan Mikami in which he specifically discusses late 60 /early 70s Tokyo scene and his involvement (or lack thereof) in the student movement. I can't remember where I read it though.