As challenging as it is for monolingual English speakers to learn of secondary literature on the Pastorals in other languages which look something like English, it is considerably more challenging to discover works published in languages which look nothing like English!
I provide here a list of Japanese-language resources on the Pastorals compiled by Manabu Tsuji (Academia page), Professor of Religious Studies at Hiroshima University, who has published extensively on the letters. Dr. Tsuji, who is producing a Japanese-language commentary on the letters — Bokkai Shokan [The Pastoral Epistles] (Tokyo: Shinkyo Shuppansha, forthcoming 2022) — graciously interacted about the list, provided English-language translations for the titles of the works, and indicated his willingness to share the Japanese-language articles with those interested. If you should happen to want one of the Japanese-language essays listed, please contact me at chuckbumgardner (at) gmail.com.
Click here to view the list.