 According to the Tokyo urban transportation plan, however, it is more complicated.The line number assigned to the section south from Kotake-Mukaihara to Shin-Kiba is Line 8, but that north of Kotake-Mukaihara to Wakōshi is Line 13, which indicates the section is a portion of Fukutoshin Line which shares the same number.The Yurakucho Line has inter-running counterparts on its northern side, both of which are "major" Japanese private railway companies in Greater Tokyo.