@Eirikr: Personally I have never seen 頭胸(とうきょう) (tōkyō) and I see only 頭胸部(とうきょうぶ) (tōkyōbu). They are equally old according to Google Books: 1901 vs. 1901. They may or may not be independent. — TAKASUGI Shinji (talk) 23:23, 17 September 2019 (UTC)Reply