Down the end of a long hall that you get to via the entrance on the unnamed west-east street that runs between the JR and Metro Akihabara stations, just south of both of them. You will see the sign outside if you look for it, picture above. 7 seats, very cramped if I remember correctly. Excellent pork. Ask for no raw egg ("nama tamago nuki de") and a bit of extra soup ("shiru mo sukoshi onegai shimasu". The small is actually quite large. and they are very generous with the garlic, but not the yasai. Self service water is also crammed in there somehow too. Good option for the Akihabara area that does not appear to be that well-known yet but is well-ranked on Tabelog and Ramen Database.