Another thing that astonishes are rather flat tuition fees, which never leave the range between 150.000JPY and 220.000JPY for a term, everything included.
So now I included some more contacts which I think are good picks, for the one or another reason. See the list below:
LABO Japanese Language Institute
focused on "cultural exchange", has severeal language foreign langugae courses, so no Ghetto, about 140.000JPY/3months. No Infos on accomod.
Located:Shinjuku
Tokyo Central Japanese Language School
Includes Teacher-Education, nothing on accomodiation. Course 44.000JPY/month
Located: Shibuya (near Shinjuku, Yoyogi Park)
Tokyo Riverside School
Fall-Term fpr 175.000JPY, no infos on accomodiation
Located:Taito (Ueno, Asakusa, really just at the riverside)
AN Language School
Nice site, only to mention its-"Learner-Based" System, price is 150000/3mon
Located:Toshima (Ikebukuro)
Tokyo Shibaura Institute of foreign Language
No Short-Courses, perhaps on request.
Located:Minato (directly at the harbour!)
Shurin Japanese School
Nice Site, 150.000JPY/term, school-owned dorm, no further infos, Jap.-Teacher education.
Located:Koto (East)