My comment:
(a) Until today, I have been unaware of what is said in quotation. But it turns out to be true.
(b)
(i) Japanese Wikipedia (ja.wikipedia.org) does have pages for 内地 (Japan proper; kanji: 日本本土) and 外地 (属地; ja.wikipedia.org specifically states that laws of Japan presently identifies 属地 as 'outside Japan'), respectively within the frame of 大日本帝国憲法 (1890-1947; also known as 明治憲法 or 帝国憲法; followed by 日本国憲法 currently in effect).
(ii) In Japan, 内地 and 外地 are pronounced "na-i-chi" and "ga-i-chi." respectively.