There seem to be two active groups in Ibaraki. One of them is ABADA Capoeira Ibaraki (webpage is in Japanese). They currently train once a week on Saturdays near Ushiku (about 20km south of Tsukuba City center). The trainer speaks Portuguese which is translated to Japanese by one of the students. There are English speaking students there too. Monthly fee is 5000 yen. If you send them an email they will get back to you.
The other Capoeira group is Filhos de Terra.