Board members and auditors in Nippon Telegraph and Telephone Corporation (NTT) and in the Regional Companies whose shares NTT owns are required to have Japanese nationality.
"Article 1(1) Nippon Telegraph and Telephone Corporation (hereinafter referred to as the "Company") is a stock company whose purpose is to own all the shares issued by Nippon Telegraph and Telephone East Corporation and Nippon Telegraph and Telephone West Corporation, to ensure that appropriate and stable telecommunications services are provided by these two companies, as well as to conduct research on telecommunications technologies that would form the basis of telecommunications.
(2)　Nippon Telegraph and Telephone East Corporation and Nippon Telegraph and Telephone West Corporation (hereinafter collectively referred to as "the Regional Companies") are stock companies whose purpose is to manage regional telecommunications business.
[...]
Article 10(1) Any person who does not have Japanese nationality may not be appointed as a director or an auditor for the Company or the Regional Companies.[...]" (Act on Nippon Telegraph and Telephone Corporation (No. 85 of December 25, 1984) Articles 1 and 10 [unofficial translation])
Act on Nippon Telegraph and Telephone Corporation (No. 85 of December 25, 1984), Articles 1 and 10
[<a href="https://elaws.e-gov.go.jp/document?lawid=359AC0000000085">Act</a>],[<a href="https://www.japaneselawtranslation.go.jp/en/laws/view/3768">Act_Eng</a>]