クローディーヌ...! (Claudine...!)

Read (Portuguese, Turkish, and Spanish Versions).

Available Summary:

The story is narrated by an unnamed psychiatrist as he reflects on the life and loves of Claude, the child of an aristocratic French family in the early 20th century. Assigned female at birth, Claude (born and often referred to throughout the story as Claudine) has identified as a boy since the age of eight; Claude's parents take him to the psychiatrist, who befriends Claude after confirming that he is in good health.

As a teenager, Claude falls in love with Maura, a servant in his family's house. Though Maura loves him in turn, she goes back to her home after the death of her father. As a high school student, Claude falls in love with Cecilia, a librarian at his school. Cecilia does not reciprocate his feelings, and is, in fact, secretly having an affair with Claude's father, Auguste; Louis, Cecilia's brother who himself had an affair with Auguste in his youth, kills Cecilia and Auguste out of jealousy.

Later, as he works towards his master's degree, Claude falls in love with a ballet dancer name Sirène. The two begin a relationship, though Sirène eventually falls in love with and becomes engaged to one of Claude's brothers. Believing that his female body makes him an "imperfect man", and with a final appeal to Sirène having been ignored, Claude falls into despair and commits suicide. In a closing narration, the psychiatrist confides to the audience that he has "no hesitation" in his belief that Claude is a trans man.

-Wikipedia.

Note from Jack:

I really, really want to read this manga, but I'm struggling to access an English language version of it. From what I understand, this is the earliest manga to feature an unambiguously trans protagonist, making it historically significant.