TSF

Japanese Wikipedia has an article on:

TSF (ジャンル)

Wikipedia ^ja

From English transsexual + fiction or fantasy.

• IPA^(key):

T(ティー)S(エス)F(エフ) • (tī-esu-efu) 

1. fiction with central themes of genderswapping, genderbending, or sex change
   • 1999, 月下 , 月下の図書館‎, archived from the original on October 8, 1999:

     基本的にはＴＳＦ（トランスセクシャルフィクション）という、男が女になってなんやかや、という作品ばかりです。

     Basically, it's all about TSF (Transsexual Fiction), where men turn into women and various things happen, in those works.

   • 2000 December 31, 月華 , “第一回「私がＴＳＦ小説を書く理由」”, in TS-WEEK‎, archived from the original on April 29, 2001:

     ＴＳＦ小説というジャンル同様、ＴＳＦ嗜好もマイナーと言えます。

     Like the TSF novel genre, TSF preferences could also be considered niche.

   • 2016 July 19, F_TSF, “TSFジャンルについての私見”, in TSFのF ‎, archived from the original on February 10, 2017:

     ＴＳＦとは、「非現実的な事象によって精神が帰属する肉体の性別が変化することで、肉体的性別と精神的性別との差異が突如うまれる物語」の類型を表す言葉として使われています。

     TSF stands for "Transsexual Fiction," a term used to describe stories where the gender of the body to which the mind belongs changes due to unreal events, creating a sudden difference between physical and mental gender.

   • 2017 July 26, Chiaki Hirai, “An Analysis of Magical Sex-Change (TSF) Manga”, in Anime Feminist‎, archived from the original on July 28, 2017:

     the crux of a TSF story relies on the biological change of the body

   • 2022 May 25, Natalie Neumann, “Natalie Rambles About TSF”, in Natalie.TF‎, archived from the original on December 1, 2022:

     I have come to the conclusion that there is no meaningful difference between the terms. TG (Trans-Gender), TSF (Trans-Sexual Fantasy or Trans-Sexual Fiction), Gender Bender, Gender Swap, or any related terminology, are all synonyms for the same concept.

• 性(せい)転(てん)換(かん)もの (seitenkan-mono)

• T(ティー)S(エス) (tī-esu)